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C-Kermit 8.0 Unix Hints and Tips
Frank da Cruz
[1]The Kermit Project, [2]Columbia University
As of: C-Kermit 8.0.211 10 April 2004
This page last updated: Fri Apr 16 16:13:14 2004 (New York USA Time)
IF YOU ARE READING A PLAIN-TEXT version of this document, note it
is a plain-text dump of a Web page. You can visit the original (and
possibly more up-to-date) Web page here:
[3]http://www.columbia.edu/kermit/ckubwr.html
Since the material in this file has been accumulating since 1985,
some (much) of it might be dated. [4]Feedback from experts on
particular OS's and platforms is always welcome.
[ [5]C-Kermit ] [ [6]Installation Instructions ] [ [7]TUTORIAL ]
________________________________________________________________________
CONTENTS
1. [8]INTRODUCTION
2. [9]PREBUILT C-KERMIT BINARIES
3. [10]PLATFORM-SPECIFIC NOTES
4. [11]GENERAL UNIX-SPECIFIC LIMITATIONS AND BUGS
5. [12]INITIALIZATION AND COMMAND FILES
6. [13]COMMUNICATION SPEED SELECTION
7. [14]COMMUNICATIONS AND DIALING
8. [15]HARDWARE FLOW CONTROL
9. [16]TERMINAL CONNECTION AND KEY MAPPING
10. [17]FILE TRANSFER
11. [18]EXTERNAL FILE TRANSFER PROTOCOLS
12. [19]SECURITY
13. [20]MISCELLANEOUS USER REPORTS
14. [21]THIRD-PARTY DRIVERS
Quick Links: [ [22]Linux ] [ [23]*BSD ] [[24]Mac OS X] [ [25]AIX ] [
[26]HP-UX ] [ [27]Solaris ] [ [28]SCO ] [ [29]DEC/Compaq ]
________________________________________________________________________
1. INTRODUCTION
[ [30]Top ] [ [31]Contents ] [ [32]Next ]
SECTION CONTENTS
1.1. [33]Documentation
1.2. [34]Technical Support
1.3. [35]The Year 2000
1.4. [36]The Euro
THIS IS WHAT USED TO BE CALLED the "beware file" for the Unix version
of C-Kermit, previously distributed as ckubwr.txt and, before that, as
ckuker.bwr, after the fashion of old Digital Equipment Corporation
(DEC) software releases that came with release notes (describing what
had changed) and a "beware file" listing known bugs, limitations,
"non-goals", and things to watch out for. The C-Kermit beware file has
been accumulating since 1985, and it applies to many different
hardware platforms and operating systems, and many versions of them,
so it is quite large. Prior to C-Kermit 8.0, it was distributed only
in plain-text format. Now it is available as a Web document with
links, internal cross references, and so on, to make it easier to use.
This document applies to Unix C-Kermit in general, as well as to
specific Unix variations like [37]Linux, [38]AIX, [39]HP-UX,
[40]Solaris, and so on, and should be read in conjunction with the
[41]platform-independent C-Kermit beware file, which contains similar
information, but applying to all versions of C-Kermit (VMS, Windows,
OS/2, AOS/VS, VOS, etc, as well as to Unix).
There is much in this document that is (only) of historical interest.
The navigation links should help you skip directly to the sections
that are relevant to you. Numerous offsite Web links are supposed to
lead to further information but, as you know, Web links go stale
frequently and without warning. If you can supply additional,
corrected, updated, or better Web links, please feel free to [42]let
us know.
1.1. Documentation
[ [43]Top ] [ [44]Contents ] [ [45]Next ]
C-Kermit 6.0 is documented in the book [46]Using C-Kermit, Second
Edition, by Frank da Cruz and Christine M. Gianone, Digital Press,
Burlington, MA, USA, ISBN 1-55558-164-1 (1997), 622 pages. This
remains the definitive C-Kermit documentation. Until the third edition
is published (sorry, there is no firm timeframe for this), please also
refer to:
[47]Supplement to Using C-Kermit, Second Edition, For C-Kermit 7.0
Thorough documentation of features new to version 7.0.
[48]Supplement to Using C-Kermit, Second Edition, For C-Kermit 8.0
Thorough documentation of features new to version 8.0.
1.2. Technical Support
[ [49]Top ] [ [50]Contents ] [ [51]Section Contents ] [ [52]Next ] [
[53]Previous ]
For information on how to get technical support, please visit:
[54]http://www.columbia.edu/kermit/support.html
1.3. The Year 2000
[ [55]Top ] [ [56]Contents ] [ [57]Section Contents ] [ [58]Next ] [
[59]Previous ]
The Unix version of C-Kermit, release 6.0 and later, is "Year 2000
compliant", but only if the underlying operating system is too.
Contact your Unix operating system vendor to find out which operating
system versions, patches, hardware, and/or updates are required.
(Quite a few old Unixes are still in operation in the new millenium,
but with their date set 28 years in the past so at least the non-year
parts of the calendar are correct.)
As of C-Kermit 6.0 (6 September 1996), post-millenium file dates are
recognized, transmitted, received, and reproduced correctly during the
file transfer process in C-Kermit's File Attribute packets. If
post-millenium dates are not processed correctly on the other end,
file transfer still takes place, but the modification or creation date
of the received file might be incorrect. The only exception would be
if the "file collision update" feature is being used to prevent
unnecessary transfer of files that have not changed since the last
time a transfer took place; in this case, a file might be transferred
unnecessarily, or it might not be transferred when it should have
been. Correct operation of the update feature depends on both Kermit
programs having the correct date and time.
Of secondary importance are the time stamps in the transaction and/or
debug logs, and the date-related script programming constructs, such
as \v(date), \v(ndate), \v(day), \v(nday), and perhaps also the
time-related ones, \v(time) and \v(ntime), insofar as they might be
affected by the date. The \v(ndate) is a numeric-format date of the
form yyyymmdd, suitable for both lexical and numeric comparison and
sorting: e.g. 19970208 or 20011231. If the underlying operating system
returns the correct date information, these variables will have the
proper values. If not, then scripts that make decisions based on these
variables might not operate correctly.
Most date-related code is based upon the C Library asctime() string,
which always has a four-digit year. In Unix, the one bit of code in
C-Kermit that is an exception to this rule is several calls to
localtime(), which returns a pointer to a tm struct, in which the year
is presumed to be expressed as "years since 1900". The code depends on
this assumption. Any platforms that violate it will need special
coding. As of this writing, no such platforms are known.
Command and script programming functions that deal with dates use
C-Kermit specific code that always uses full years.
1.4. The Euro
[ [60]Top ] [ [61]Contents ] [ [62]Section Contents ] [ [63]Previous ]
C-Kermit 7.0 and later support Unicode (ISO 10646), ISO 8859-15 Latin
Alphabet 9, PC Code Page 858, Windows Code Pages 1250 and 1251, and
perhaps other character sets, that encode the Euro symbol, and can
translate among them as long as no intermediate character-set is
involved that does not include the Euro.
________________________________________________________________________
2. PREBUILT C-KERMIT BINARIES
[ [64]Top ] [ [65]Contents ] [ [66]Next ] [ [67]Previous ]
It is often dangerous to run a binary C-Kermit (or any other) program
built on a different computer. Particularly if that computer had a
different C compiler, libraries, operating system version, processor
features, etc, and especially if the program was built with shared
libraries, because as soon as you update the libraries on your system,
they no longer match the ones referenced in the binary, and the binary
might refuse to load when you run it, in which case you'll see error
messages similar to:
Could not load program kermit
Member shr4.o not found or file not an archive
Could not load library libcurses.a[shr4.o]
Error was: No such file or directory
(These samples are from AIX.) To avoid this problem, we try to build
C-Kermit with statically linked libraries whenever we can, but this is
increasingly impossible as shared libraries become the norm.
It is often OK to run a binary built on an earlier OS version, but it
is rarely possible (or safe) to run a binary built on a later one, for
example to run a binary built under Solaris 8 on Solaris 2.6.
Sometimes even the OS-or-library patch/ECO level makes a difference.
A particularly insidious problem occurs when a binary was built on a
version of the OS that has patches from the vendor (e.g. to
libraries); in many cases you won't be able to run such a binary on an
unpatched version of the same platform.
When in doubt, build C-Kermit from the source code on the computer
where it is to be run (if possible!). If not, ask us for a binary
specific to your configuration. We might have one, and if we don't, we
might be able to find somebody who will build one for you.
________________________________________________________________________
3. NOTES ON SPECIFIC UNIX VERSIONS
[ [68]Top ] [ [69]Contents ] [ [70]Next ] [ [71]Previous ]
SECTION CONTENTS
3.0. [72]C-KERMIT ON PC-BASED UNIXES
3.1. [73]C-KERMIT AND AIX
3.2. [74]C-KERMIT AND HP-UX
3.3. [75]C-KERMIT AND LINUX
3.4. [76]C-KERMIT AND NEXTSTEP
3.5. [77]C-KERMIT AND QNX
3.6. [78]C-KERMIT AND SCO
3.7. [79]C-KERMIT AND SOLARIS
3.8. [80]C-KERMIT AND SUNOS
3.9. [81]C-KERMIT AND ULTRIX
3.10. [82]C-KERMIT AND UNIXWARE
3.11. [83]C-KERMIT AND APOLLO SR10
3.12. [84]C-KERMIT AND TANDY XENIX 3.0
3.13. [85]C-KERMIT AND OSF/1 (DIGITAL UNIX) (TRU64 UNIX)
3.14. [86]C-KERMIT AND SGI IRIX
3.15. [87]C-KERMIT AND THE BEBOX
3.16. [88]C-KERMIT AND DG/UX
3.17. [89]C-KERMIT AND SEQUENT DYNIX
3.18. [90]C-KERMIT AND {FREE,OPEN,NET}BSD
3.19. [91]C-KERMIT AND MAC OS X
3.20. [92]C-KERMIT AND COHERENT
The following sections apply to specific Unix versions. Most of them
contain references to FAQs (Frequently Asked Questions), but these
tend to be ephemeral. For possibly more current information see:
[93]http://www.faqs.org
[94]http://aplawrence.com/Unixart/newtounix.html
One thread that runs through many of them, and implicitly perhaps
through all, concerns the problems that occur when trying to dial out
on a serial device that is (also) enabled for dialing in. The
"solutions" to this problem are many, varied, diverse, and usually
gross, involving configuring the device for bidirectional use. This is
done in a highly OS-dependent and often obscure manner, and the
effects (good or evil) are also highly dependent on the particular OS
(and getty variety, etc). Many examples are given in the
[95]OS-specific sections below.
An important point to keep in mind is that C-Kermit is a
cross-platform, portable software program. It was not designed
specifically and only for your particular Unix version, or for that
matter, for Unix in particular at all. It also runs on VMS, AOS/VS,
VOS, and other non-Unix platforms. All the Unix versions of C-Kermit
share common i/o modules, with compile-time #ifdef constructions used
to account for the differences among the many Unix products and
releases. If you think that C-Kermit is behaving badly or missing
something on your particular Unix version, you might be right -- we
can't claim to be expert in hundreds of different OS / version /
hardware / library combinations. If you're a programmer, take a look
at the source code and [96]send us your suggested fixes or changes. Or
else just [97]send us a report about what seems to be wrong and we'll
see what we can do.
________________________________________________________________________
3.0. C-KERMIT ON PC-BASED UNIXES
[ [98]Top ] [ [99]Contents ] [ [100]Section Contents ] [ [101]Next ]
Also see: [102]http://www.pcunix.com/.
SECTION CONTENTS
3.0.1. [103]Interrupt Conflicts
3.0.2. [104]Windows-Specific Hardware
3.0.3. [105]Modems
3.0.4. [106]Character Sets
3.0.5. [107]Keyboard, Screen, and Mouse Access
3.0.6. [108]Laptops
3.0.1. Interrupt Conflicts
[ [109]Top ] [ [110]Contents ] [ [111]Section Contents ] [ [112]Next ]
PCs are not the best platform for real operating systems like Unix.
The architecture suffers from numerous deficiencies, not the least of
which is the stiflingly small number of hardware interrupts (either 7
or 15, many of which are preallocated). Thus adding devices, using
multiple serial ports, etc, is always a challenge and often a
nightmare. The free-for-all nature of the PC market and the lack of
standards combined with the diversity of Unix OS versions make it
difficult to find drivers for any particular device on any particular
version of Unix.
Of special interest to Kermit users is the fact that there is no
standard provision in the PC architecture for more than 2
communication (serial) ports. COM3 and COM4 (or higher) will not work
unless you (a) find out the hardware address and interrupt for each,
(b) find out how to provide your Unix version with this information,
and (c) actually set up the configuration in the Unix startup files
(or whatever other method is used). Watch out for interrupt conflicts,
especially when using a serial mouse, and don't expect to be able to
use more than two serial ports.
The techniques for resolving interrupt conflicts are different for
each operating system (Linux, NetBSD, etc). In general, there is a
configuration file somewhere that lists COM ports, something like
this:
com0 at isa? port 0x3f8 irq 4 # DOS COM1
com1 at isa? port 0x2f8 irq 3 # DOS COM2
The address and IRQ values in this file must agree with the values in
the PC BIOS and with the ports themselves, and there must not be more
than one device with the same interrupt. Unfortunately, due to the
small number of available interrupts, installing new devices on a PC
almost always creates a conflict. Here is a typical tale from a Linux
user (Fred Smith) about installing a third serial port:
...problems can come from a number of causes. The one I fought with
for some time, and finally conquered, was that my modem is on an
add-in serial port, cua3/IRQ5. By default IRQ5 has a very low
priority, and does not get enough service in times when the system
is busy to prevent losing data. This in turn causes many resends.
There are two 'fixes' that I know of, one is to relax hard disk
interrupt hogging by using the correct parameter to hdparm, but I
don't like that one because the hdparm man page indicates it is
risky to use. The other one, the one I used, was to get 'irqtune'
and use it to give IRQ5 the highest priority instead of nearly the
lowest. Completely cured the problem.
Here's another one from a newsgroup posting:
After much hair pulling, I've discovered why my serial port won't
work. Apparently my [PC] has three serial devices (two comm ports
and an IR port), of which only two at a time can be active. I
looked in the BIOS setup and noticed that the IR port was
activated, but didn't realize at the time that this meant that COM2
was thereby de-activated. I turned off the IR port and now the
serial port works as advertised.
________________________________________________________________________
3.0.2. Windows-Specific Hardware
[ [113]Top ] [ [114]Contents ] [ [115]Section Contents ] [ [116]Next ]
[ [117]Previous ]
To complicate matters, the PC platform is becoming increasingly and
inexorably Windows-oriented. More and more add-on devices are "Windows
only" -- meaning they are incomplete and rely on proprietary
Windows-based software drivers to do the jobs that you would expect
the device itself to do. PCMCIA, PCI, or "Plug-n-Play" devices are
rarely supported on PC-based Unix versions such as SCO; Winmodems,
Winprinters, and the like are not supported on any Unix variety (with
[118]a few exceptions). The self-proclaimed Microsoft PC 97 (or later)
standard only makes matters worse since its only purpose to ensure
that PCs are "optimized to run Windows 95 and Windows NT 4.0 and
future versions of these operating systems".
With the exception noted (the Lucent modem, perhaps a handful of
others by the time you read this), drivers for "Win" devices are
available only for Windows, since the Windows market dwarfs that of
any particular Unix brand, and for that matter all Unixes (or for that
matter, all non-Windows operating systems) combined. If your version
of Unix (SCO, Linux, BSDI, FreeBSD, etc) does not support a particular
device, then C-Kermit can't use it either. C-Kermit, like any Unix
application, must access all devices through drivers and not directly
because Unix is a real operating system.
Don't waste time thinking that you, or anybody else, could write a
Linux (or other Unix) driver for a Winmodem or other "Win" device.
First of all, these devices generally require realtime control, but
since Unix is a true multitasking operating system, realtime device
control is not possible outside the kernel. Second, the specifications
for these devices are secret and proprietary, and each one (and each
version of each one) is potentially different. Third, a Winmodem
driver would be enormously complex; it would take years to write and
debug, by which time it would be obsolete.
A more recent generation of PCs (circa 1999-2000) is marketed as
"Legacy Free". One can only speculate what that could mean. Most
likely it means it will ONLY run the very latest versions of Windows,
and is made exclusively of Winmodems, Winprinters, Winmemory, and
Win-CPU-fans (Legacy Free is a concept [119]pioneered by Microsoft).
Before you buy a new PC or add-on equipment, especially serial ports,
internal modems, or printers, make sure they are compatible with your
version of Unix. This is becoming an ever-greater challenge; only a
huge company like Microsoft can afford to be constantly cranking out
and/or verifying drivers for the thousands of video boards, sound
cards, network adapters, SCSI adapters, buses, etc, that spew forth in
an uncontrolled manner from all corners of the world on a daily basis.
With very few exceptions, makers of PCs assemble the various
components and then verify them only with Windows, which they must do
since they are, no doubt, preloading the PC with Windows. To find a
modern PC that is capable of running a variety of non-Windows
operating systems (e.g. Linux, SCO OpenServer, Unixware, and Solaris)
is a formidable challenge requiring careful study of each vendor's
"compatibility lists" and precise attention to exact component model
numbers and revision levels.
________________________________________________________________________
3.0.3. Modems
[ [120]Top ] [ [121]Contents ] [ [122]Section Contents ] [ [123]Next ]
[ [124]Previous ]
External modems are recommended:
* They don't need any special drivers.
* You can use the lights and speaker to troubleshoot dialing.
* You can share them among all types of computers.
* You can easily turn them off and on when power-cycling seems
warranted.
* They are more likely to have manuals.
Internal PC modems (even when they are not Winmodems, which is
increasingly unlikely in new PCs) are always trouble, especially in
Unix. Even when they work for dialing out, they might not work for
dialing in, etc. Problems that occur when using an internal modem can
almost always be eliminated by switching to an external one. Even when
an internal modem is not a Winmodem or Plug-n-Play, it is often a
no-name model of unknown quality -- not the sort of thing you want
sitting directly on your computer's bus. (Even if it does not cause
hardware problems, it probably came without a command list, so no Unix
software will know how to control it.) For more about Unix compatible
modems, see:
[125]http://www.idir.net/~gromitkc/winmodem.html
Remember that PCs, even now -- more than two decades after they were
first introduced -- are not (in general) capable of supporting more
than 2 serial devices. Here's a short success story from a recent
newsgroup posting: "I have a Diamond SupraSonic II dual modem in my
machine. What I had to end up doing is buying a PS/2 mouse and port
and install it. Had to get rid of my serial mouse. I also had to
disable PnP in my computer bios. I was having IRQ conflicts between my
serial mouse and 'com 3'. Both modems work fine for me. My first modem
is ttyS0 and my second is ttyS1." Special third-party multiport boards
such as [126]DigiBoard are available for certain Unix platforms
(typically SCO, maybe Linux) that come with special platform-specific
drivers.
________________________________________________________________________
3.0.4. Character Sets
[ [127]Top ] [ [128]Contents ] [ [129]Section Contents ] [ [130]Next ]
[ [131]Previous ]
PCs generally have PC code pages such as CP437 or CP850, and these are
often used by PC-based Unix operating systems, particularly on the
console. These are supported directly by C-Kermit's SET FILE
CHARACTER-SET and SET TERMINAL CHARACTER-SET commands. Some PC-based
Unix versions, such as recent Red Hat Linux releases, might also
support Microsoft Windows code pages such as CP1252, or even Latin
Alphabet 1 itself (perhaps displayed with CP437 glyphs). (And work is
in progress to support Unicode UTF8 in Linux.)
Certain Windows code pages are not supported directly by C-Kermit, but
since they are ISO Latin Alphabets with nonstandard "extensions" in
the C1 control range, you can substitute the corresponding Latin
alphabet (or other character set) in any C-Kermit character-set
related commands:
Windows Code Page Substitution
CP 1004 Latin-1
CP 1051 HP Roman-8
Other Windows code pages are mostly (or totally) incompatible with
their Latin Alphabet counterparts (e.g. CP1250 and Latin-2), and
several of these are already supported by C-Kermit 7.0 and later
(1250, 1251, and 1252).
________________________________________________________________________
3.0.5. Keyboard, Screen, and Mouse Access
[ [132]Top ] [ [133]Contents ] [ [134]Section Contents ] [ [135]Next ]
[ [136]Previous ]
Finally, note that as a real operating system, Unix (unlike Windows)
does not provide the intimate connection to the PC keyboard, screen,
and mouse that you might expect. Unix applications can not "see" the
keyboard, and therefore can not be programmed to understand F-keys,
Editing keys, Arrow keys, Alt-key combinations, and the like. This is
because:
a. Unix is a portable operating system, not only for PCs;
b. Unix sessions can come from anywhere, not just the PC's own
keyboard and screen; and:
c. even though it might be possible for an application that actually
is running on the PC's keyboard and screen to access these devices
directly, there are no APIs (outside of X) for this.
________________________________________________________________________
3.0.6. Laptops
[ [137]Top ] [ [138]Contents ] [ [139]Section Contents ] [
[140]Previous ]
(To be filled in . . .)
________________________________________________________________________
3.1. C-KERMIT AND AIX
[ [141]Top ] [ [142]Contents ] [ [143]Section Contents ] [ [144]Next ]
[ [145]Previous ]
SECTION CONTENTS
3.1.1. [146]AIX: General
3.1.2. [147]AIX: Network Connections
3.1.3. [148]AIX: Serial Connections
3.1.4. [149]AIX: File Transfer
3.1.5. [150]AIX: Xterm Key Map
For additional information see:
* [151]http://www.emerson.emory.edu/services/aix-faq/
* [152]http://www.faqs.org/faqs/by-newsgroup/comp/comp.unix.aix.html
* [153]http://www.cis.ohio-state.edu/hypertext/faq/usenet/aix-faq/to
p.html
* [154]http://aixpdslib.seas.ucla.edu/
* [155]http://www.rootvg.net (AIX history)
* [156]ftp://rtfm.mit.edu/pub/usenet/news.answers/aix-faq/part1
* [157]ftp://mirrors.aol.com/pub/rtfm/usenet-by-hierarchy/comp/unix/
aix
and/or read the [158]comp.unix.aix newsgroup.
______________________________________________________________________
3.1.1. AIX: General
[ [159]Top ] [ [160]Contents ] [ [161]Section Contents ] [ [162]Next ]
About AIX version numbers: "uname -a" tells the two-digit version
number, such as 3.2 or 4.1. The three-digit form can be seen with the
"oslevel" command (this information is unavailable at the API level
and is reportedly obtained by scanning the installed patch list).
Supposedly all three-digit versions within the same two-digit version
(e.g. 4.3.1, 4.3.2) are binary compatible; i.e. a binary built on any
one of them should run on all others, but who knows. Most AIX
advocates tell you that any AIX binary will run on any AIX version
greater than or equal to the one under which it was built, but
experience with C-Kermit suggests otherwise. It is always best to run
a binary built under your exact same AIX version, down to the third
decimal place, if possible. Ideally, build it from source code
yourself. Yes, this advice would be easier to follow if AIX came with
a C compiler.
______________________________________________________________________
3.1.2. AIX: Network Connections
[ [163]Top ] [ [164]Contents ] [ [165]Section Contents ] [ [166]Next ]
[ [167]Previous ]
File transfers into AIX 4.2 or 4.3 through the AIX Telnet or Rlogin
server have been observed to fail (or accumulate huge numbers of
correctable errors, or even disconnect the session), when exactly the
same kind of transfers into AIX 4.1 work without incident, as do such
transfers into all non-AIX platforms on the same kind of connections
(with a few exceptions noted elsewhere in this document). AIX 4.3.3
seems to be particularly fragile in this regard; the weakness seems to
be in its pseudoterminal (pty) driver. High-speed streaming transfers
work perfectly, however, if the AIX Telnet server and pty driver are
removed from the picture; e.g, by using "set host * 3000" on AIX.
The problem can be completely cured by replacing the IBM Telnet server
with [168]MIT's Kerberos Telnet server -- even if you don't actually
use the Kerberos part. Diagnosis: AIX pseudoterminals (which are
controlled by the Telnet server to give you a login terminal for your
session) have quirks that not even IBM knows about. The situation with
AIX 5.x is not known, but if it has the same problem, the same cure is
available.
Meanwhile, the only remedy when going through the IBM Telnet server is
to cut back on Kermit's performance settings until you find a
combination that works:
* SET STREAMING OFF
* SET WINDOW-SIZE small-number
* SET { SEND, RECEIVE } PACKET-LENGTH small-number
* SET PREFIXING { CAUTIOUS, ALL }
In some cases, severe cutbacks are required, e.g. those implied by the
ROBUST command. Also be sure that the AIX C-Kermit on the remote end
has "set flow none" (which is the default). NOTE: Maybe this one can
also be addressed by starting AIX telnetd with the "-a" option. The
situation with SSH connections is not known, but almost certainly the
same.
When these problems occur, the system error log contains:
LABEL: TTY_TTYHOG
IDENTIFIER: 0873CF9F
Type: TEMP
Resource Name: pts/1
Description
TTYHOG OVER-RUN
Failure Causes
EXCESSIVE LOAD ON PROCESSOR
Recommended Actions
REDUCE SYSTEM LOAD.
REDUCE SERIAL PORT BAUD RATE
Before leaving the topic of AIX pseudoterminals, it is very likely
that Kermit's PTY and SSH commands do not work well either, for the
same reason that Telnet connections into AIX don't work well. A brief
test with "pty rlogin somehost" got a perfectly usable terminal
(CONNECT) session, but file-transfer problems like those just
described.
Reportedly, telnet from AIX 4.1-point-something to non-Telnet ports
does not work unless the port number is in the /etc/services file;
it's not clear from the report whether this is a problem with AIX
Telnet (in which case it would not affect Kermit), or with the sockets
library (in which case it would). The purported fix is IBM APAR
IX61523.
C-Kermit SET HOST or TELNET from one AIX 3.1 (or earlier) system to
another won't work right unless you set your local terminal type to
something other than AIXTERM. When your terminal type is AIXTERM, AIX
TELNET sends two escapes whenever you type one, and the AIX telnet
server swallows one of them. This has something to do with the "hft"
device. This behavior seems to be removed in AIX 3.2 and later.
______________________________________________________________________
3.1.3. AIX: Serial Connections
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[ [173]Previous ]
In AIX 3, 4, or 5, C-Kermit won't be able to "set line /dev/tty0" (or
any other dialout device) if you haven't installed "cu" or "uucp" on
your system, because installing these is what creates the UUCP
lockfile directory. If SET LINE commands always result in "Sorry,
access to lock denied", even when C-Kermit has been given the same
owner, group, and permissions as cu:
-r-sr-xr-x 1 uucp uucp 67216 Jul 27 1999 cu
and even when you run it as root, then you must go back and install
"cu" from your AIX installation media.
According to IBM's "From Strength to Strength" document (21 April
1998), in AIX 4.2 and later "Async supports speeds on native serial
ports up to 115.2kbps". However, no API is documented to achieve
serial speeds higher than 38400 bps. Apparently the way to do this --
which might or might not work only on the IBM 128-port multiplexer --
is:
cxma-stty fastbaud /dev/tty0
which, according to "man cxma-stty":
fastbaud Alters the baud rate table, so 50 baud becomes 57600 baud.
-fastbaud Restores the baud rate table, so 57600 baud becomes 50
baud.
Presumably (but not certainly) this extrapolates to 110 "baud" becomes
76800 bps, and 150 becomes 115200 bps. So to use high serial speeds in
AIX 4.2 or 4.3, the trick would be to give the "cxma-stty fastbaud"
command for the desired tty device before starting Kermit, and then
use "set speed 50", "set speed 110", or "set speed 150" to select
56700, 76800, or 115200 bps. It is not known whether cxma-stty
requires privilege.
According to one report, "Further investigation with IBM seems to
indicate that the only hardware capable of doing this is the 128-port
multiplexor with one (or more) of the 16 port breakout cables
(Enhanced Remote Async Node 16-Port EIA-232). We are looking at about
CDN$4,000 in hardware just to hang a 56kb modem on there. Of course,
we can then hang 15 more, if we want. This hardware combo is described
to be good to 230.4kbps."
Another report says (quote from AIX newsgroup, March 1999):
The machine type and the adapter determine the speed that one can
actually run at. The older microchannel machines have much slower
crystal frequencies and may not go beyond 76,800. A feature put
into AIX 421 allows one to key in non-POSIX baud rates and if the
uart can support that speed, it will get set. this applies also to
43p's and beyond. 115200 is the max for the 43P's native serial
port. As crytal frequencies continue to increase, the built-in
serial ports speeds will improve. To use 'uucp' or 'ate' at the
higher baud rates, configure the port for the desired speed, but
set the speed of uucp or ate to 50. Any non-POSIX speeds set in the
ttys configuration will the be used. In the case of the 128-port
adapters or the ISA 8-port or PCI 8-port adapter, there are only a
few higher baud rates.
a. Change the port to enable high baud rates:
+ B50 for 57600
+ B75 for 76800
+ B110 for 115200
+ B200 for 230000
b. chdev -l ttyX -a fastbaud=enable
+ For the 128 ports original style rans, only 57600 bps is
supported.
+ For the new enhanced RANs, up to 230Kbps is supported.
In AIX 2.2.1 on the RT PC with the 8-port multiplexer, SET SPEED 38400
gives 9600 bps, but SET SPEED 19200 gives 19200 (on the built-in S1
port).
Note that some RS/6000s (e.g. the IBM PowerServer 320) have
nonstandard rectangular 10-pin serial ports; the DB-25 connector is
NOT a serial port; it is a parallel printer port. IBM cables are
required for the serial ports, (The IBM RT PC also had rectangular
serial ports -- perhaps the same as these, perhaps different.)
If you dial in to AIX through a modem that is connected directly to an
AIX port (e.g. on the 128-port multiplexer) and find that data is
lost, especially when uploading files to the AIX system (and system
error logs report buffer overruns on the port):
1. Make sure the port and modem are BOTH configured for hardware
(RTS/CTS) flow control. The port is configured somewhere in the
system configuration, outside of Kermit.
2. Tell C-Kermit to "set flow keep"; experimentation shows that SET
FLOW RTS/CTS has no effect when used in remote mode (i.e. on
/dev/tty, as opposed to a specify port device).
3. Fixes for bugs in the original AIX 4.2 tty (serial i/o) support
and other AIX bugs are available from IBM at:
[174]http://service.software.ibm.com/rs6000/
Downloads -> Software Fixes -> Download FixDist gets an
application for looking up known problems.
Many problems reported with bidirectional terminal lines on AIX 3.2.x
on the RS/6000. Workaround: don't use bidirectional terminal lines, or
write a shell-script wrapper for Kermit that turns getty off on the
line before starting Kermit, or before Kermit attempts to do the SET
LINE. (But note: These problems MIGHT be fixed in C-Kermit 6.0 and
later.) The commands for turning getty off and on (respectively) are
/usr/sbin/pdisable and /usr/sbin/penable.
______________________________________________________________________
3.1.4. AIX: File Transfer
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[ [179]Previous ]
Evidently AIX 4.3 (I don't know about earlier versions) does not allow
open files to be overwritten. This can cause Kermit transfers to fail
when FILE COLLISION is OVERWRITE, where they might work on other Unix
varieties or earlier AIX versions.
Transfer of binary -- and maybe even text -- files can fail in AIX if
the AIX terminal has particular port can have character-set
translation done for it by the tty driver. The following advice from a
knowledgeable AIX user:
[This feature] has to be checked (and set/cleared) with a separate
command, unfortunately stty doesn't handle this. To check:
$ setmaps
input map: none installed
output map: none installed
If it says anything other than "none installed" for either one, it
is likely to cause a problem with kermit. To get rid of installed
maps:
$ setmaps -t NOMAP
However, I seem to recall that with some versions of AIX before
3.2.5, only root could change the setting. I'm not sure what
versions - it might have only been under AIX 3.1 that this was
true. At least with AIX 3.2.5 an ordinary user can set or clear the
maps.
On the same problem, another knowledgeable AIX user says:
The way to get information on the NLS mapping under AIX (3.2.5
anyway) is as follows. From the command line type:
lsattr -l tty# -a imap -a omap -E -H
Replace the tty number for the number sign above. This will give a
human readable output of the settings that looks like this;
# lsattr -l tty2 -a imap -a omap -E -H
attribute value description user_settable
imap none INPUT map file True
omap none OUTPUT map file True
If you change the -H to a -O, you get output that can easily be
processed by another program or a shell script, for example:
# lsattr -l tty2 -a imap -a omap -E -O
#imap:omap
none:none
To change the settings from the command line, the chdev command is
used with the following syntax.
chdev -l tty# -a imap='none' -a omap='none'
Again substituting the appropriate tty port number for the number
sign, "none" being the value we want for C-Kermit. Of course, the
above can also be changed by using the SMIT utility and selecting
devices - tty. (...end quote)
______________________________________________________________________
3.1.5. AIX: Xterm Key Map
[ [180]Top ] [ [181]Contents ] [ [182]Section Contents ] [
[183]Previous ]
Here is a sample configuration for setting up an xterm keyboard for
VT220 or higher terminal emulation on AIX, courtesy of Bruce Momjian,
Drexel Hill, PA. Xterm can be started like this:
xterm $XTERMFLAGS +rw +sb +ls $@ -tm 'erase ^? intr ^c' -name vt220 \
-title vt220 -tn xterm-220 "$@" &
---------------------------------------------------------------------------
XTerm*VT100.Translations: #override \n\
<Key>Home: string(0x1b) string("[3~") \n \
<Key>End: string(0x1b) string("[4~") \n
vt220*VT100.Translations: #override \n\
Shift <Key>F1: string("[23~") \n \
Shift <Key>F2: string("[24~") \n \
Shift <Key>F3: string("[25~") \n \
Shift <Key>F4: string("[26~") \n \
Shift <Key>F5: string("[K~") \n \
Shift <Key>F6: string("[31~") \n \
Shift <Key>F7: string("[31~") \n \
Shift <Key>F8: string("[32~") \n \
Shift <Key>F9: string("[33~") \n \
Shift <Key>F10: string("[34~") \n \
Shift <Key>F11: string("[28~") \n \
Shift <Key>F12: string("[29~") \n \
<Key>Print: string(0x1b) string("[32~") \n\
<Key>Cancel: string(0x1b) string("[33~") \n\
<Key>Pause: string(0x1b) string("[34~") \n\
<Key>Insert: string(0x1b) string("[2~") \n\
<Key>Delete: string(0x1b) string("[3~") \n\
<Key>Home: string(0x1b) string("[1~") \n\
<Key>End: string(0x1b) string("[4~") \n\
<Key>Prior: string(0x1b) string("[5~") \n\
<Key>Next: string(0x1b) string("[6~") \n\
<Key>BackSpace: string(0x7f) \n\
<Key>Num_Lock: string(0x1b) string("OP") \n\
<Key>KP_Divide: string(0x1b) string("Ol") \n\
<Key>KP_Multiply: string(0x1b) string("Om") \n\
<Key>KP_Subtract: string(0x1b) string("OS") \n\
<Key>KP_Add: string(0x1b) string("OM") \n\
<Key>KP_Enter: string(0x1b) string("OM") \n\
<Key>KP_Decimal: string(0x1b) string("On") \n\
<Key>KP_0: string(0x1b) string("Op") \n\
<Key>KP_1: string(0x1b) string("Oq") \n\
<Key>KP_2: string(0x1b) string("Or") \n\
<Key>KP_3: string(0x1b) string("Os") \n\
<Key>KP_4: string(0x1b) string("Ot") \n\
<Key>KP_5: string(0x1b) string("Ou") \n\
<Key>KP_6: string(0x1b) string("Ov") \n\
<Key>KP_7: string(0x1b) string("Ow") \n\
<Key>KP_8: string(0x1b) string("Ox") \n\
<Key>KP_9: string(0x1b) string("Oy") \n
! <Key>Up: string(0x1b) string("[A") \n\
! <Key>Down: string(0x1b) string("[B") \n\
! <Key>Right: string(0x1b) string("[C") \n\
! <Key>Left: string(0x1b) string("[D") \n\
*visualBell: true
*saveLines: 1000
*cursesemul: true
*scrollKey: true
*scrollBar: true
________________________________________________________________________
3.2. C-KERMIT AND HP-UX
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[ [188]Previous ]
SECTION CONTENTS
3.2.0. [189]Common Problems
3.2.1. [190]Building C-Kermit on HP-UX
3.2.2. [191]File Transfer
3.2.3. [192]Dialing Out and UUCP Lockfiles in HP-UX
3.2.4. [193]Notes on Specific HP-UX Releases
3.2.5. [194]HP-UX and X.25
REFERENCES
For further information, read the [195]comp.sys.hp.hpux newsgroup.
C-Kermit is included as part of the HP-UX operating system by contract
between Hewlett Packard and Columbia University for HP-UX 10.00 and
later. Each level of HP-UX includes a freshly built C-Kermit binary in
/bin/kermit, which should work correctly. Binaries built for regular
HP-UX may be used on Trusted HP-UX and vice-versa, except for use as
IKSD because of the different authentication methods.
Note that HP does not update C-Kermit versions for any but its most
current HP-UX release. So, for example, HP-UX 10.20 has C-Kermit 6.0;
11.00 has C-Kermit 7.0, and 11.22 has 8.0. Of course, as with all
software, older Kermit versions have bugs (such as buffer overflow
vulnerabilities) that are fixed in later versions. From time to time,
HP discovers one of these (long-ago fixed) bugs and issues a security
alert for the older OS's, recommending some draconian measure to avoid
the problem. The true fix in each situation is to install the current
release of C-Kermit.
3.2.0. Common Problems
[ [196]Top ] [ [197]Contents ] [ [198]Section Contents ] [ [199]Next ]
Some HP workstations have a BREAK/RESET key. If you hit this key while
C-Kermit is running, it might kill or suspend the C-Kermit process.
C-Kermit arms itself against these signals, but evidently the
BREAK/RESET key is -- at least in some circumstances, on certain HP-UX
versions -- too powerful to be caught. (Some report that the first
BREAK/RESET shows up as SIGINT and is caught by C-Kermit's former
SIGINT handler even when SIGINT is currently set to SIG_IGN; the
second kills Kermit; other reports suggest the first BREAK/RESET sends
a SIGTSTP (suspend signal) to Kermit, which it catches and suspends
itself. You can tell C-Kermit to ignore suspend signals with SET
SUSPEND OFF. You can tell C-Kermit to ignore SIGINT with SET COMMAND
INTERRUPTION OFF. It is not known whether these commands also grant
immunity to the BREAK/RESET key (one report states that with SET
SUSPEND OFF, the BREAK/RESET key is ignored the first four times, but
kills Kermit the 5th time). In any case:
1. If this key is mapped to SIGINT or SIGTSTP, C-Kermit catches or
ignores it, depending on which mode (CONNECT, command, etc) Kermit
is in.
2. If it causes HP-UX to kill C-Kermit, there is nothing C-Kermit can
do to prevent it.
When HP-UX is on the remote end of the connection, it is essential
that HP-UX C-Kermit be configured for Xon/Xoff flow control (this is
the default, but in case you change it and then experience
file-transfer failures, this is a likely reason).
________________________________________________________________________
3.2.1. Building C-Kermit on HP-UX
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This section applies mainly to old (pre-10.20) HP-UX version on
old, slow, and/or memory-constrained hardware.
During the C-Kermit 6.0 Beta cycle, something happened to ckcpro.w
(or, more precisely, the ckcpro.c file that is generated from it)
which causes HP optimizing compilers under HP-UX versions 7.0 and 8.0
(apparently on all platforms) as well as under HP-UX 9.0 on Motorola
platforms only, to blow up. In versions 7.0 and 8.0 the problem has
spread to other modules.
The symptoms vary from the system grinding to a halt, to the compiler
crashing, to the compilation of the ckcpro.c module taking very long
periods of time, like 9 hours. This problem is handled by compiling
the modules that tickle it without optimization; the new C-Kermit
makefile takes care of this, and shows how to do it in case the same
thing begins happening with other modules.
On HP-UX 9.0, a kernel parameter, maxdsiz (maximum process data
segment size), seems to be important. On Motorola systems, it is 16MB
by default, whereas on RISC systems the default is much bigger.
Increasing maxdsiz to about 80MB seems to make the problem go away,
but only if the system also has a lot of physical memory -- otherwise
it swaps itself to death.
The optimizing compiler might complain about "some optimizations
skipped" on certain modules, due to lack of space available to the
optimizer. You can increase the space (the incantation depends on the
particular compiler version -- see the [205]makefile), but doing so
tends to make the compilations take a much longer time. For example,
the "hpux0100o+" makefile target adds the "+Onolimit" compiler flag,
and about an hour to the compile time on an HP-9000/730. But it *does*
produce an executable that is about 10K smaller :-)
In the makefile, all HP-UX entries automatically skip optimization of
problematic modules.
________________________________________________________________________
3.2.2. File Transfer
[ [206]Top ] [ [207]Contents ] [ [208]Section Contents ] [ [209]Next ]
[ [210]Previous ]
Telnet connections into HP-UX versions up to and including 11.11 (and
possibly 11.20) tend not to lend themselves to file transfer due to
limitations, restrictions, and/or bugs in the HP-UX Telnet server
and/or pseudoterminal (pty) driver.
In C-Kermit 6.0 (1996) an unexpected slowness was noted when
transferring files over local Ethernet connections when an HP-UX
system (9.05 or 10.00) was on the remote end. The following experiment
was conducted to determine the cause. C-Kermit 6.0 was used; the
situation is slightly better using C-Kermit 7.0's streaming feature
and HP-UX 10.20 on the far end.
The systems were HP-UX 10.00 (on 715/33) and SunOS 4.1.3 (on
Sparc-20), both on the same local 10Mbps Ethernet, packet length 4096,
parity none, control prefixing "cautious", using only local disks on
each machine -- no NFS. In the C-Kermit 6.0 (ACK/NAK) case, the window
size was 20; in the streaming case there is no window size (i.e. it is
infinite). The test file was C-Kermit executable, transferred in
binary mode. Conditions were relatively poor: the Sun and the local
net heavily loaded; the HP system is old, slow, and
memory-constrained.
C-Kermit 6.0... C-Kermit 7.0...
Local Remote ACK/NAK........ Streaming......
Client Server Send Receive Send Receive
Sun HP 36 18 64 18
HP HP 25 15 37 16
HP Sun 77 83 118 92
Sun Sun 60 60 153 158
So whenever HP is the remote we have poor performance. Why?
* Changing file display to CRT has no effect (so it's not the curses
library on the client side).
* Changing TCP RECV-BUFFER or SEND-BUFFER has little effect.
* Telling the client to make a binary-mode connection (SET TELNET
BINARY REQUESTED, which successfully negotiates a binary
connection) has no effect on throughput.
BUT... If I start HP-UX C-Kermit as a TCP service:
set host * 3000
server
and then from the client "set host xxx 3000", I get:
C-Kermit 6.0... C-Kermit 7.0...
Local Remote ACK/NAK........ Streaming......
Client Server Send Receive Send Receive
Sun HP 77 67 106 139
HP HP 50 50 64 62
HP Sun 57 85 155 105
Sun Sun 57 50 321 314
Therefore the HP-UX telnet server or pty driver seems to be adding
more overhead than the SunOS one, and most others. When going through
this type of connection (a remote telnet server) there is little
Kermit can do improve matters, since the telnet server and pty driver
are between the two Kermits, and neither Kermit program can have any
influence over them (except putting the Telnet connection in binary
mode, but that doesn't help).
(The numbers for the HP-HP transfers are lower than the others since
both Kermit processes are running on the same slow 33MHz CPU.)
Matters seem to have deteriorated in HP-UX 11. Now file transfers over
Telnet connections fail completely, rather than just being slow. In
the following trial, a Telnet connection was made from Kermit 95 to
HP-UX 11.11 on an HP-9000/785/B2000 over local 10Mbps Ethernet running
C-Kermit 8.00 in server mode (under the HP-UX Telnet server):
Text........ Binary......
Stream Pktlen GET SEND GET SEND
On 4000 Fail Fail Fail Fail
Off 4000 Fail Fail Fail Fail
Off 2000 OK Fail OK Fail
On 2000 OK Fail OK Fail
On 3000 Fail Fail Fail Fail
On 2500 Fail Fail Fail Fail
On 2047 OK Fail OK Fail
On 2045 OK Fail OK Fail
Off 500 OK OK OK OK
On 500 OK Fail OK Fail
On 240 OK Fail OK Fail
As you can see, downloads are problematic unless the receiver's Kermit
packet length is 2045 or less, but uploads work only with streaming
disabled and the packet length restricted to 500. To force file
transfers to work on this connection, the desktop Kermit must be told
to:
set streaming off
set receive packet-length 2000
set send packet-length 500
However, if a connection is made between the same two programs on the
same two computers over the same network, but this time a direct
socket-to-socket connection bypassing the HP-UX Telnet server and pty
driver (tell HP-UX C-Kermit to "set host /server * 3000 /raw"; tell
desktop client program to "set host blah 3000 /raw"), everything works
perfectly with the default Kermit settings (streaming, 4K packets,
liberal control-character unprefixing, 8-bit transparency, etc):
Text........ Binary......
Stream Pktlen GET SEND GET SEND
On 4000 OK OK OK OK
And in this case, transfer rates were approximately 900,000 cps. To
verify that the behavior reported here is not caused by the new Kermit
release, the same experiment was performed on a Telnet connection from
the same PC over the same network to the old 715/33 running HP-UX
10.20 and C-Kermit 8.00. Text and binary uploads and downloads worked
perfectly (albeit slowly) with all the default settings -- streaming,
4K packets, etc.
________________________________________________________________________
3.2.3. Dialing Out and UUCP Lockfiles in HP-UX
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[ [215]Previous ]
HP workstations do not come with dialout devices configured; you have
to do it yourself (as root). First look in /dev to see what's there;
for example in HP-UX 10.00 or later:
ls -l /dev/cua*
ls -l /dev/tty*
If you find a tty0p0 device but no cua0p0, you'll need to creat one if
you want to dial out; the tty0p0 does not work for dialing out. It's
easy: start SAM; in the main Sam window, double-click on Peripheral
Device, then in the Peripheral Devices window, double-click on
Terminals and Modems. In the Terminals and Modems dialog, click on
Actions, then choose "Add modem" and fill in the blanks. For example:
Port number 0, speed 57600 (higher speeds tend not to work reliably),
"Use device for calling out", do NOT "Receive incoming calls" (unless
you know what you are doing), leave "CCITT modem" unchecked unless you
really have one, and do select "Use hardware flow control (RTS/CTS)".
Then click OK. This creates cua0p0 as well as cul0p0 and ttyd0p0
If the following sequence:
set line /dev/cua0p0 ; or other device
set speed 115200 ; or other normal speed
produces the message "?Unsupported line speed". This means either that
the port is not configured for dialout (go into SAM as described above
and make sure "Use device for calling out" is selected), or else that
speed you have given (such as 460800) is supported by the operating
system but not by the physical device (in which case, use a lower
speed like 57600).
In HP-UX 9.0, serial device names began to change. The older names
looked like "/dev/cua00", "/dev/tty01", etc (sometimes with only one
digit). The newer names have two digits with the letter "p" in
between. HP-UX 8.xx and earlier have the older form, HP-UX 10.00 and
later have the newer form. HP-UX 9.xx has the newer form on Series 800
machines, and the older form on other hardware models. The situation
is summarized in the following table (the Convio 10.0 column applies
to HP-UX 10 and 11).
Converged HP-UX Serial I/O Filenames : TTY Mux Naming
---------------------------------------------------------------------
General meaning Old Form S800 9.0 Convio 10.0
---------------------------------------------------------------------
tty* hardwired ports tty<YY> tty<X>p<Y> tty<D>p<p>
diag:mux<X> diag:mux<D>
---------------------------------------------------------------------
ttyd* dial-in modems ttyd<YY> ttyd<X>p<Y> ttyd<D>p<p>
diag:ttyd<X>p<Y> diag:ttyd<D>p<p>
---------------------------------------------------------------------
cua* auto-dial out cua<YY> cua<X>p<Y> cua<D>p<p>
diag:cua<X>p<Y>
---------------------------------------------------------------------
cul* dial-out cul<YY> cul<X>p<Y> cul<D>p<p>
diag:cul<X>p<Y>
---------------------------------------------------------------------
<X>= LU (Logical Unit) <D>= Devspec (decimal card instance)
<Y> or <YY> = Port <p>= Port
For dialing out, you should use the cua or cul devices. When
C-Kermit's CARRIER setting is AUTO or ON, C-Kermit should pop back to
its prompt automatically if the carrier signal drops, e.g. when you
log out from the remote computer or service. If you use the tty<D>p<d>
(e.g. tty0p0) device, the carrier signal should be ignored. The
tty<D>p<d> device should be used for direct connections where the
carrier signal does not follow RS-232 conventions (use the cul device
for hardwired connections through a true null modem). Do not use the
ttyd<D>p<d> device for dialing out.
Kermit's access to serial devices is controlled by "UUCP lockfiles",
which are intended to prevent different users using different software
programs (Kermit, cu, etc, and UUCP itself) from accessing the same
serial device at the same time. When a device is in use by a
particular user, a file with a special name is created in:
/var/spool/locks (HP-UX 10.00 and later)
/usr/spool/uucp (HP-UX 9.xx and earlier)
The file's name indicates the device that is in use, and its contents
indicates the process ID (pid) of the process that is using the
device. Since serial devices and the locks directory are not both
publicly readable and writable, Kermit and other communication
software must be installed setuid to the owner (bin) of the serial
device and setgid to the group (daemon) of the /var/spool/locks
directory. Kermit's setuid and setgid privileges are enabled only when
opening the device and accessing the lockfiles.
Let's say "unit" means a string of decimal digits (the interface
instance number) followed (in HP-UX 10.00 and later) by the letter "p"
(lowercase), followed by another string of decimal digits (the port
number on the interface), e.g.:
"0p0", "0p1", "1p0", etc (HP-UX 10.00 and later)
"0p0", "0p1", "1p0", etc (HP-UX 9.xx on Series 800)
"00", "01", "10", "0", etc (HP-UX 9.xx not on Series 800)
"00", "01", "10", "0", etc (HP-UX 8.xx and earlier)
Then a normal serial device (driver) name consists of a prefix ("tty",
"ttyd", "cua", "cul", or possibly "cuad" or "culd") followed by a
unit, e.g. "cua0p0". Kermit's treatment of UUCP lockfiles is as close
as possible to that of the HP-UX "cu" program. Here is a table of the
lockfiles that Kermit creates for unit 0p0:
Selection Lockfile 1 Lockfile 2
/dev/tty0p0 LCK..tty0p0 (none)
* /dev/ttyd0p0 LCK..ttyd0p0 (none)
/dev/cua0p0 LCK..cua0p0 LCK..ttyd0p0
/dev/cul0p0 LCK..cul0p0 LCK..ttyd0p0
/dev/cuad0p0 LCK..cuad0p0 LCK..ttyd0p0
/dev/culd0p0 LCK..culd0p0 LCK..ttyd0p0
<other> LCK..<other> (none)
(* = Dialin device, should not be used.)
In other words, if the device name begins with "cu", a second lockfile
for the "ttyd" device, same unit, is created, which should prevent
dialin access on that device.
The <other> case allows for symbolic links, etc, but of course it is
not foolproof since we have no way of telling which device is really
being used.
When C-Kermit tries to open a dialout device whose name ends with a
"unit", it searches the lockfile directory for all possible names for
the same unit. For example, if user selects /dev/cul2p3, Kermit looks
for lockfiles named:
LCK..tty2p3
LCK..ttyd2p3
LCK..cua2p3
LCK..cul2p3
LCK..cuad2p3
LCK..culd2p3
If any of these files are found, Kermit opens them to find out the ID
(pid) of the process that created them; if the pid is still valid, the
process is still active, and so the SET LINE command fails and the
user is informed of the pid so s/he can use "ps" to find out who is
using the device.
If the pid is not valid, the file is deleted. If all such files (i.e.
with same "unit" designation) are successfully removed, then the SET
LINE command succeeds; up to six messages are printed telling the user
which "stale lockfiles" are being removed.
When the "set line" command succeeds in HP-UX 10.00 and later,
C-Kermit also creates a Unix System V R4 "advisory lock" as a further
precaution (but not guarantee) against any other process obtaining
access to the device while you are using it.
If the selected device was in use by "cu", Kermit can't open it,
because "cu" has changed its ownership, so we never get as far as
looking at the lockfiles. In the normal case, we can't even look at
the device to see who the owner is because it is visible only to its
(present) owner. In this case, Kermit says (for example):
/dev/cua0p0: Permission denied
When Kermit releases a device it has successfully opened, it removes
all the lockfiles that it created. This also happens whenever Kermit
exits "under its own power".
If Kermit is killed with a device open, the lockfile(s) are left
behind. The next Kermit program that tries to assign the device, under
any of its various names, will automatically clean up the stale
lockfiles because the pids they contain are invalid. The behavior of
cu and other communication programs under these conditions should be
the same.
Here, by the way, is a summary of the differences between the HP-UX
port driver types from John Pezzano of HP:
There are three types of device files for each port.
The ttydXXX device file is designed to work as follows:
1. The process that opens it does NOT get control of the port until
CD is asserted. This was intentional (over 15 years ago) to allow
getty to open the port but not control it until someone called in.
If a process wants to use the direct or callout device files
(ttyXXX and culXXX respectively), they will then get control and
getty would be blocked. This eliminated the need to use uugetty
(and its inherent problems with lock files) for modems. You can
see this demonstrated by the fact that "ps -ef" shows a ? in the
tty column for the getty process as getty does not have the port
yet.
2. Once CD is asserted, the port is controlled by getty (or the
process handling an incoming call) if there was no process using
the port. The ? in the "ps" command now shows the port. At this
point, the port accepts data.
Therefore you should use either the callout culXXX device file
(immediate control but no data until CD is asserted) or the direct
device file ttyXXX which gives immediate control and immediate data
and which ignores by default modem control signals.
The ttydXXX device should be used only for callin and my
recommendation is to use it only for getty and uugetty.
________________________________________________________________________
3.2.4 Notes on Specific HP-UX Releases
SECTION CONTENTS
3.2.4.1. [216]HP-UX 11
3.2.4.2. [217]HP-UX 10
3.2.4.3. [218]HP-UX 9
3.2.4.4. [219]HP-UX 8
3.2.4.5. [220]HP-UX 7 and Earlier
3.2.4.1. HP-UX 11
[ [221]Top ] [ [222]Contents ] [ [223]Section Contents ] [ [224]Next ]
As noted in [225]Section 3.2.2, the HP-UX 11 Telnet server and/or
pseudoterminal driver are a serious impediment to file transfer over
Telnet connections into HP-UX. If you have a Telnet connection into
HP-UX 11, tell your desktop Kermit program to:
set streaming off
set receive packet-length 2000
set send packet-length 500
File transfer speeds over connections from HP-UX 11 (dialed or Telnet)
are not impeded whatsoever, and can go at whatever speed is allowed by
the connection and the Kermit partner on the far end.
PA-RISC binaries for HP-UX 10.20 or later should run on any PA-RISC
system, S700 or S800, as long as the binary was not built under a
later HP-UX version than the host operating system. HP-UX 11.00 and
11.11 are only for PA-RISC systems. HP-UX 11.20 is only for IA64
(subsequent HP-UX releases will be for both PA-RISC and IA64). To
check binary compatibility, the following C-Kermit 8.0 binaries were
run successfully on an HP-9000/785 with HP-UX 11.11:
* Model 7xx HP-UX 10.20
* Model 8xx HP-UX 10.20
* Model 7xx HP-UX 11.00
* Model 8xx HP-UX 11.00
* Model 7xx HP-UX 11.11
* Model 8xx HP-UX 11.11
Binaries built under some of the earlier HP-UX releases, such as 9.05,
might also work, but only if built for the same hardware family (e.g.
s700).
________________________________________________________________________
3.2.4.2. HP-UX 10
[ [226]Top ] [ [227]Contents ] [ [228]Section Contents ] [ [229]Next ]
[ [230]Previous ]
Beginning in HP-UX 10.10, libcurses is linked to libxcurses, the new
UNIX95 (X/Open) version of curses, which has some serious bugs; some
routines, when called, would hang and never return, some would dump
core. Evidently libxcurses contains a select() routine, and whenever
C-Kermit calls what it thinks is the regular (sockets) select(), it
gets the curses one, causing a segmentation fault. There is a patch
for this from HP, PHCO_8086, "s700_800 10.10 libcurses patch", "shared
lib curses program hangs on 10.10", "10.10 enhanced X/Open curses core
dumps due to using wrong select call", 96/08/02 (you can tell if the
patch is installed with "what /usr/lib/libxcurses.1"; the unpatched
version is 76.20, the patched one is 76.20.1.2). It has been verified
that C-Kermit works OK with the patched library, but results are not
definite for HP-UX 10.20 or higher.
To ensure that C-Kermit works even on non-patched HP-UX 10.10 systems,
separate makefile entries are provided for HP-UX 10.00/10.01, 10.10,
10.20, etc, in which the entries for 10.10 and above link with
libHcurses, which is "HP curses", the one that was used in
10.00/10.01. HP-UX 11.20 and later, however, link with libcurses, as
libHcurses disappeared in 11.20.
________________________________________________________________________
3.2.4.3. HP-UX 9
[ [231]Top ] [ [232]Contents ] [ [233]Section Contents ] [ [234]Next ]
[ [235]Previous ]
HP-UX 9.00 and 9.01 need patch PHNE_10572 (note: this replaces
PHNE_3641) for hptt0.o, asio0.o, and ttycomn.o in libhp-ux.a. Contact
Hewlett Packard if you need this patch. Without it, the dialout device
(tty) will be hung after first use; subsequent attempts to use will
return an error like "device busy". (There are also equivalent patches
for s700 9.03 9.05 9.07 (PHNE_10573) and s800 9.00 9.04 (PHNE_10416).
When C-Kermit is in server mode, it might have trouble executing
REMOTE HOST commands. This problem happens under HP-UX 9.00 (Motorola)
and HP-UX 9.01 (RISC) IF the C-Shell is the login shell AND with the
C-Shell Revision 70.15. Best thing is to install HP's Patch PHCO_4919
for Series 300/400 and PHCO_5015 for the Series 700/800. PHCO_5015 is
called "s700_800 9.X cumulative csh(1) patch with memory leak fix"
which works for HP-UX 9.00, 9.01, 9.03, 9.04, 9.05 and 9.07. At least
you need C-Shell Revision 72.12!
C-Kermit works fine -- including its curses-based file-transfer
display -- on the console terminal, in a remote session (e.g. when
logged in to the HP 9000 on a terminal port or when telnetted or
rlogin'd), and in an HP-VUE hpterm window or an xterm window.
________________________________________________________________________
3.2.4.4. HP-UX 8
[ [236]Top ] [ [237]Contents ] [ [238]Section Contents ] [ [239]Next ]
[ [240]Previous ]
To make C-Kermit work on HP-UX 8.05 on a model 720, obtain and install
HP-UX patch PHNE_0899. This patch deals with a lot of driver issues,
particularly related to communication at higher speeds.
One user reports:
On HP-UX 8 DON'T install 'tty patch' PHKL_4656, install PHKL_3047
instead! Yesterday I tried this latest tty patch PHKL_4656 and had
terrible problems. This patch should fix RTS/CTS problems. With
text transver all looks nice. But when I switched over to binary
files the serial interface returned only rubish to C-Kermit. All
sorts of protocol, CRC and packed errors I had. After several tests
and after uninstalling that patch, all transvers worked fine. MB's
of data without any errors. So keep your fingers away from that
patch. If anybody needs the PHKL_3047 patch I have it here. It is
no longer availabel from HP's patch base.
________________________________________________________________________
3.2.4.5. HP-UX 7 and Earlier
[ [241]Top ] [ [242]Contents ] [ [243]Section Contents ] [
[244]Previous ]
When transferring files into HP-UX 5 or 6 over a Telnet connection,
you must not use streaming, and you must not use a packet length
greater than 512. However, you can use streaming and longer packets
when sending files from HP-UX on a Telnet connection. In C-Kermit 8.0,
the default receive packet length for HP-UX 5 and 6 was changed to 500
(but you can still increase it with SET RECEIVE PACKET-LENGTH if you
wish, e.g. for non-Telnet connections). Disable streaming with SET
STREAMING OFF.
The HP-UX 5.00 version of C-Kermit does not include the fullscreen
file-transfer because of problems with the curses library.
If HP-UX 5.21 with Wollongong TCP/IP is on the remote end of a Telnet
connection, streaming transfers to HP-UX invariably fail. Workaround:
SET STREAMING OFF. Packets longer than about 1000 should not be used.
Transfers from these systems, however, can use streaming and/or longer
packets.
Reportedly, "[there is] a bug in C-Kermit using HP-UX version 5.21 on
the HP-9000 series 500 computers. It only occurs when the controlling
terminal is using an HP-27140 six-port modem mux. The problem is not
present if the controlling terminal is logged into an HP-27130
eight-port mux. The symptom is that just after dialing successfully
and connecting Kermit locks up and the port is unusable until both
forks of Kermit and the login shell are killed." (This report predates
C-Kermit 6.0 and might no longer apply.)
________________________________________________________________________
3.2.5. HP-UX and X.25
[ [245]Top ] [ [246]Contents ] [ [247]Section Contents ] [
[248]Previous ]
Although C-Kermit presently does not include built-in support for
HP-UX X.25 (as it does for the Sun and IBM X.25 products), it can
still be used to make X.25 connections as follows: start Kermit and
then telnet to localhost. After logging back in, start padem as you
would normally do to connect over X.25. Padem acts as a pipe between
Kermit and X.25. In C-Kermit 7.0, you might also be able to avoid the
"telnet localhost" step by using:
C-Kermit> pty padem address
This works if padem uses standard i/o (who knows?).
________________________________________________________________________
3.3. C-KERMIT AND LINUX
[ [249]Top ] [ [250]Contents ] [ [251]Section Contents ] [ [252]Next ]
[ [253]Previous ]
SECTION CONTENTS
3.3.1. [254]Problems Building C-Kermit for Linux
3.3.2. [255]Problems with Serial Devices in Linux
3.3.3. [256]Terminal Emulation in Linux
3.3.4. [257]Dates and Times
3.3.5. [258]Startup Errors
3.3.6. [259]The Fullscreen File Transfer Display
REFERENCES
For further information, read the [260]comp.os.linux.misc,
[261]comp.os.linux.answers, and other Linux-oriented newsgroups, and
see:
The Linux Document Project (LDP)
[262]http://www.tldp.org/
The Linux FAQ
[263]http://www.tldp.org/FAQ/Linux-FAQ.html
The Linux HOWTOs (especially the Serial HOWTO)
[264]http://www.tldp.org/HOWTO/Serial-HOWTO.html
[265]http://tldp.org/HOWTO/Modem-HOWTO.html
[266]ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO
[267]ftp://tsx-11.mit.edu/pub/linux/docs/HOWTO
[268]http://www.tldp.org/HOWTO/
[269]http://www.tldp.org/hmirrors.html
Linux Vendor Tech Support Pages:
[270]http://www.redhat.com/apps/support/
[271]http://www.debian.org/support
[272]http://www.slackware.com/support/
[273]http://www.caldera.com/support/
[274]http://www.suse.com/support/
[275]http://www.mandrake.com/support/
[276]http://www.turbolinux.com/support/
Linux Winmodem Support
[277]http://www.linmodems.org/
Also see general comments on PC-based Unixes in [278]Section 3.0.
What Linux version is it? -- "uname -a" supplies only kernel
information, but these days it's the distribution that matters: Red
Hat 7.3, Debian 2.2, Slackware 8.0, etc. Unfortunately there's no
consistent way to get the distribution version. Usually it's in a
distribution-specific file:
Red Hat: /etc/issue or /etc/redhat-release
Debian: /etc/debian_version
Slackware: /etc/slackware-version (at least in later versions)
Did you know: DECnet is available for Linux? See:
[279]http://linux.dreamtime.org/decnet/
(But there is no support for it in C-Kermit -- anybody interested in
adding it, please [280]let us know).
Before proceeding, let's handle the some of the most frequently asked
question in the Linux newsgroups:
1. Neither C-Kermit nor any other Linux application can use
Winmodems, except in the [281]rare cases where Linux drivers have
been written for them. See [282]Section 3.0.2 for details.
2. "Why does it take such a long time to make a telnet connection to
(or from) my Linux PC?" (this applies to C-Kermit and to regular
Telnet). Most telnet servers these days perform reverse DNS
lookups on the client (for security and/or logging reasons). If
the Telnet client's address cannot be found by the server's local
DNS server, the DNS request goes out to the Internet at large, and
this can take quite some time. The solution to this problem is to
make sure that both client and host are registered in DNS, and
that the registrations are exported. C-Kermit itself performs
reverse DNS lookups unless you tell it not to; this is to allow
C-Kermit to let you know which host it is actually connected to in
case you have made a connection to a host pool (multihomed host).
You can disable C-Kermit's reverse DNS lookup with SET TCP
REVERSE-DNS-LOOKUP OFF.
3. (Any question that has the word "Telnet" in it...) The knee-jerk
reaction is "don't use Telnet, use SSH!" There's nothing wrong
with Telnet. In fact it's far superior to SSH as a protocol in
terms of features and extensibility, not to mention platform
neutrality. The issue lurking behind the knee-jerk reaction is
security. SSH is thought to be secure, whereas Telnet is thought
to be insecure. This is true for clear-text Telnet (because
passwords travel in the clear across the network), but apparently
few people realize that [283]secure Telnet clients and servers
have been available for years, and these are more secure than SSH
(for reasons explained [284]HERE.
4. (Any question that has the word "FTP" in it...) The knee-jerk
reaction being "Don't use FTP, use SCP!" (or SFTP). Same answer as
above, but moreso. SCP and SFTP are not only not platform neutral,
they're diversity-hostile. They transfer files only in binary
mode, which mangles text files across different platforms, to the
same degree the platform's text-file record format and character
set differ. An extreme example would be an Variable-Block format
EBCDIC text file on an IBM mainframe, binary transfer of which to
Unix would do you little good indeed. FTP was designed with
diversity in mind and secure versions are available.
________________________________________________________________________
3.3.1. Problems Building C-Kermit for Linux
[ [285]Top ] [ [286]Contents ] [ [287]Section Contents ] [ [288]Next ]
Modern Linux distributions like Red Hat give you a choice at
installation whether to include "developer tools". Obviously, you
can't build C-Kermit or any other C program from source code if you
have not installed the developer tools. But to confuse matters, you
might also have to choose (separately) to install the "curses" or
"ncurses" terminal control library; thus it is possible to install the
C compiler and linker, but omit the (n)curses library and headers. If
curses is not installed, you will not be able to build a version of
C-Kermit that supports the fullscreen file-transfer display, in which
case you'll need to use the "linuxnc" makefile target (nc = No Curses)
or else install ncurses before building.
There are all sorts of confusing issues caused by the many and varied
Linux distributions. Some of the worst involve the curses library and
header files: where are they, what are they called, which ones are
they really? Other vexing questions involve libc5 vs libc6 vs glibc vs
glibc2 (C libraries), gcc vs egcs vs lcc (compilers), plus using or
avoiding features that were added in a certain version of Linux or a
library or a distribution, and are not available in others. As of
C-Kermit 8.0, these questions should be resolved by the "linux"
makefile target itself, which does a bit of looking around to see
what's what, and then sets the appropriate CFLAGS.
________________________________________________________________________
3.3.2. Problems with Serial Devices in Linux
[ [289]Top ] [ [290]Contents ] [ [291]Section Contents ] [ [292]Next ]
[ [293]Previous ]
Also see: "man setserial", "man irqtune".
And: [294]Sections 3.0, [295]6, [296]7, and [297]8 of this
document.
NOTE: Red Hat Linux 7.2 and later include a new API that allows
serial-port arbitration by non-setuid/gid programs. This API has
not yet been added to C-Kermit. If C-Kermit is to be used for
dialing out on Red Hat 7.2 or later, it must still be installed as
described in in Sections [298]10 and [299]11 of the
[300]Installation Instructions.
Don't expect it to be easy. Queries like the following are posted to
the Linux newsgroups almost daily:
Problem of a major kind with my Compaq Presario 1805 in the sense
that the pnpdump doesn't find the modem and the configuration tells
me that the modem is busy when I set everything by hand!
I have <some recent SuSE distribution>, kernel 2.0.35. Using the
Compaq tells me that the modem (which is internal) is on COM2, with
the usual IRQ and port numbers. Running various Windows diagnostics
show me AT-style commands exchanged so I have no reason to beleive
that it is a Winmodem. Also, the diagnostics under Win98 tell me
that I am talking to an NS 16550AN.
[Editor's note: This does not necessarily mean it isn't a Winmodem.]
Under Linux, no joy trying to talk to the modem on /dev/cua1
whether via minicom, kppp, or chat; kppp at least tells me that
tcgetattr() failed.
Usage of setserial:
setserial /dev/cua1 port 0x2F8 irq 3 autoconfig
setserial -g /dev/cua1
tells me that the uart is 'unknown'. I have tried setting the UART
manullay via. setserial to 16550A, 16550, and the other one (8550?)
(I didn't try 16540). None of these manual settings resulted in any
success.
A look at past articles leads me to investigate PNP issues by
calling pnpdump but pnpdump returns "no boards found". I have
looked around on my BIOS (Phoenix) and there is not much evidence
of it being PNP aware. However for what it calls "Serial port A",
it offers a choice of Auto, Disabled or Manual settings (currently
set to Auto), but using the BIOS interface I tried to change to
'manual' and saw the default settings offered to be were 0x3F8 and
IRQ 4 (COM1). The BIOS menus did not give me any chance to
configure COM2 or any "modem". I ended up not saving any BIOS
changes in the course of my investigations.
You can also find out a fair amount about your PC's hardware
configuration in the text files in /proc, e.g.:
-r--r--r-- 1 root 0 Sep 4 14:00 /proc/devices
-r--r--r-- 1 root 0 Sep 4 14:00 /proc/interrupts
-r--r--r-- 1 root 0 Sep 4 14:00 /proc/ioports
-r--r--r-- 1 root 0 Sep 4 14:00 /proc/pci
From the directory listing they look like empty files, but in fact
they are text files that you "cat":
$ cat /proc/pci
Bus 0, device 14, function 0:
Serial controller: US Robotics/3Com 56K FaxModem Model 5610 (rev 1).
IRQ 10.
I/O at 0x1050 [0x1057].
$ setserial -g /dev/ttyS4
/dev/ttyS4, UART: 16550A, Port: 0x1050, IRQ: 10
$ cat /proc/ioports
1050-1057 : US Robotics/3Com 56K FaxModem Model 5610
1050-1057 : serial(auto)
$ cat /proc/interrupts
CPU0
0: 7037515 XT-PIC timer
1: 2 XT-PIC keyboard
2: 0 XT-PIC cascade
4: 0 XT-PIC serial
8: 1 XT-PIC rtc
9: 209811 XT-PIC usb-uhci, eth0
14: 282015 XT-PIC ide0
15: 6 XT-PIC ide1
Watch out for PCI, PCMCIA and Plug-n-Play devices, Winmodems, and the
like (see cautions in [301]Section 3.0 Linux supports Plug-n-Play
devices to some degree via the isapnp and pnpdump programs; read the
man pages for them. (If you don't have them, look on your installation
CD for isapnptool or download it from sunsite or a sunsite mirror or
other politically correct location du jour).
PCI modems do not use standard COM port addresses. The I/O address and
IRQ are assigned by the BIOS. All you need to do to get one working,
find out the I/O address and interrupt number with (as root) "lspci -v
| more" and then give the resulting address and interrupt number to
setserial.
Even when you have a real serial port, always be wary of interrupt
conflicts and similar PC hardware configuration issues: a PC is not a
real computer like other Unix workstations -- it is generally pieced
together from whatever random components were the best bargain on the
commodity market the week it was built. Once it's assembled and boxed,
not even the manufacturer will remember what it's made of or how it
was put together because they've moved on to a new model. Their job is
to get it (barely) working with Windows; for Linux and other OS's you
are on your own.
"set line /dev/modem" or "set line /dev/ttyS2", etc, results in an
error, "/dev/modem is not a tty". Cause unknown, but obviously a
driver issue, not a Kermit one (Kermit uses "isatty()" to check that
the device is a tty, so it knows it will be able to issue all the
tty-related ioctl's on it, like setting the speed & flow control). Try
a different name (i.e. driver) for the same port, e.g. "set line
/dev/cua2" or whatever.
To find what serial ports were registered at the most recent system
boot, type (as root): "grep tty /var/log/dmesg".
"set modem type xxx" (where xxx is the name of a modem) followed by
"set line /dev/modem" or "set
line /dev/ttyS2", etc, hangs (but can be interrupted with Ctrl-C).
Experimentation shows that if the modem is configured to always assert
carrier (&C0) the same command does not hang. Again, a driver issue.
Use /dev/cua2 (or whatever) instead. (Or not -- hopefully none of
these symptoms occurs in C-Kermit 7.0 or later.)
"set line /dev/cua0" reports "Device is busy", but "set line
/dev/ttyS0" works OK.
In short: If the cua device doesn't work, try the corresponding ttyS
device. If the ttyS device doesn't work, try the corresponding cua
device -- but note that Linux developers do not recommend this, and
are phasing out the cua devices. From /usr/doc/faq/howto/Serial-HOWTO:
12.4. What's The Real Difference Between the /dev/cuaN And /dev/ttySN
Devices?
The only difference is the way that the devices are opened. The
dialin devices /dev/ttySN are opened in blocking mode, until CD
is asserted (ie someone connects). So, when someone wants to
use the /dev/cuaN device, there is no conflict with a program
watching the /dev/ttySN device (unless someone is connected of
course). The multiple /dev entries, allow operation of the same
physical device with different operating characteristics. It
also allows standard getty programs to coexist with any other
serial program, without the getty being retrofitted with
locking of some sort. It's especially useful since standard
Unix kernel file locking, and UUCP locking are both advisory
and not mandatory.
It was discovered during development of C-Kermit 7.0 that rebuilding
C-Kermit with -DNOCOTFMC (No Close/Open To Force Mode Change) made the
aforementioned problem with /dev/ttyS0 go away. It is not yet clear,
however, what its affect might be on the /dev/cua* devices. As of 19
March 1998, this option has been added to the CFLAGS in the makefile
entries for Linux ("make linux").
Note that the cua device is now "deprecated", and new editions of
Linux will phase (have phased) it out in favor of the ttyS device. See
(if it's still there):
[302]http://linuxwww.db.erau.edu/mail_archives/linux-kernel/Mar_98/1441.html
(no, of course it isn't; you'll have to use your imagination). One
user reported that C-Kermit 7.0, when built with egcs 1.1.2 and run on
Linux 2.2.6 with glibc 2.1 (hardware unknown but probably a PC) dumps
core when given a "set line /dev/ttyS1" command. When rebuilt with
gcc, it works fine.
All versions of Linux seem to have the following deficiency: When a
modem call is hung up and CD drops, Kermit can no longer read the
modem signals; SHOW COMMUNICATIONS says "Modem signals not available".
The TIOCMGET ioctl() returns -1 with errno 5 ("I/O Error").
The Linux version of POSIX tcsendbreak(), which is used by C-Kermit to
send regular (275msec) and long (1.5sec) BREAK signals, appears to
ignore its argument (despite its description in the man page and info
topic), and always sends a regular 275msec BREAK. This has been
observed in Linux versions ranging from Debian 2.1 to Red Hat 7.1.
________________________________________________________________________
3.3.3. Terminal Emulation in Linux
[ [303]Top ] [ [304]Contents ] [ [305]Section Contents ] [ [306]Next ]
[ [307]Previous ]
C-Kermit is not a terminal emulator. For a brief explanation of why
not, see [308]Section 3.0.5. For a fuller explanation, [309]ClICK
HERE.
In Unix, terminal emulation is supplied by the Window in which you run
Kermit: the regular console screen, which provides Linux Console
"emulation" via the "console" termcap entry, or under X-Windows in an
xterm window, which gives VTxxx emulation. An xterm that includes
color ANSI and VT220 emulation is available with Xfree86:
[310]http://dickey.his.com/xterm/xterm.html
Before starting C-Kermit in an xterm window, you might need to tell
the xterm window's shell to "stty sane".
To set up your PC console keyboard to send VT220 key sequences when
using C-Kermit as your communications program in an X terminal window
(if it doesn't already), create a file somewhere (e.g. in /root/)
called .xmodmaprc, containing something like the following:
keycode 77 = KP_F1 ! Num Lock => DEC Gold (PF1)
keycode 112 = KP_F2 ! Keypad / => DEC PF1
keycode 63 = KP_F3 ! Keypad * => DEC PF3
keycode 82 = KP_F4 ! Keypad - => DEC PF4
keycode 111 = Help ! Print Screen => DEC Help
keycode 78 = F16 ! Scroll Lock => DEC Do
keycode 110 = F16 ! Pause => DEC Do
keycode 106 = Find ! Insert => DEC Find
keycode 97 = Insert ! Home => DEC Insert
keycode 99 = 0x1000ff00 ! Page Up => DEC Remove
keycode 107 = Select ! Delete => DEC Select
keycode 103 = Page_Up ! End => DEC Prev Screen
keycode 22 = Delete ! Backspace sends Delete (127)
Then put "xmodmap filename" in your .xinitrc file (in your login
directory), e.g.
xmodmap /root/.xmodmaprc
Of course you can move things around. Use the xev program to find out
key codes.
Console-mode keys are mapped separately using loadkeys, and different
keycodes are used. Find out what they are with showkey.
For a much more complete VT220/320 key mapping for [311]Xfree86 xterm,
[312]CLICK HERE.
________________________________________________________________________
3.3.4. Dates and Times
[ [313]Top ] [ [314]Contents ] [ [315]Section Contents ] [ [316]Next ]
[ [317]Previous ]
If C-Kermit's date-time (e.g. as shown by its DATE command) differs
from the system's date and time:
a. Make sure the libc to which Kermit is linked is set to GMT or is
not set to any time zone. Watch out for mixed libc5/libc6 systems;
each must be set indpendently.
b. If you have changed your TZ environment variable, make sure it is
exported. This is normally done in /etc/profile or /etc/TZ.
________________________________________________________________________
3.3.5. Startup Errors
[ [318]Top ] [ [319]Contents ] [ [320]Section Contents ] [ [321]Next ]
[ [322]Previous ]
C-Kermit should work on all versions of Linux current through March
2003, provided it was built on the same version you have, with the
same libraries and header files (just get the source code and "make
linux"). Binaries tend not to travel well from one Linux machine to
another, due to their many differences. There is no guarantee that a
particular C-Kermit binary will not stop working at a later date,
since Linux tends to change out from under its applications. If that
happens, rebuild C-Kermit from source. If something goes wrong with
the build process, look on the [323]C-Kermit website for a newer
version. If you have the latest version, then [324]report the problem
to us.
Inability to transfer files in Red Hat 7.2: the typical symptom would
be if you start Kermit and tell it to RECEIVE, it fails right away
with "?/dev/tty: No such device or address" or "?Bad file descriptor".
One report says this is because of csh, and if you change your shell
to bash or other shell, it doesn't happen. Another report cite bugs in
Red Hat 7.2 Telnetd "very seldom (if ever) providing a controlling
tty, and lots of other people piled on saying they have the same
problem.") A third theory is that this happens only when Linux has
been installed without "virtual terminal support".
A search of RedHat's errata pages shows a bug advisory (RHBA-2001-153)
issued 13 November 2001, but updated 6 December, about this same
symptom (but with tcsh and login.) Seems that login was not always
assigning a controlling TTY for the session, which would make most use
of "/dev/tty" somewhat less than useful.
[325]http://www.redhat.com/support/errata/RHBA-2001-153.html
Quoting: "Due to terminal handling problems in /bin/login, tcsh would
not find the controlling terminal correctly, and a shell in single
user mode would exhibit strange terminal input characteristics. This
update fixes both of these problems."
Since the Red Hat 5.1 release (circa August 1998), there have been
numerous reports of prebuilt Linux executables, and particularly the
Kermit RPM for Red Hat Linux, not working; either it won't start at
all, or it gives error messages about "terminal type unknown" and
refuses to initialize its curses support. The following is from the
[326]Kermit newsgroup:
From: rchandra@hal9000.buf.servtech.com
Newsgroups: comp.protocols.kermit.misc
Subject: Red Hat Linux/Intel 5.1 and ncurses: suggestions
Date: 22 Aug 1998 15:54:46 GMT
Organization: Verio New York
Keywords: RedHat RPM 5.1
Several factors can influence whether "linux" is recognized as a
terminal type on many Linux systems.
1. Your program, or the libraries it linked with (if statically
linked), or the libraries it dynamically links with at runtime,
are looking for an entry in /etc/termcap that isn't there. (not
likely, but possible... I believe but am not certain that this is
a very old practice in very old [n]curses library implementations
to use a single file for all terminal descriptions.)
2. Your program, or the libraries...are looking for a terminfo file
that just plain isn't there. (also not so likely, since many
people in other recent message threads said that other programs
work OK).
3. Your program, or the libraries...are looking for a terminfo file
that is stored at a pathname that isn't expected by your program,
the libraries--and so on. I forgot if I read this in the errata
Web page or where exactly I discovered this (Netscape install?
Acrobat install?), but it may just be that one libc (let's say for
sake of argument, libc5, but I don't know this to be true) expects
your terminfo to be in /usr/share/terminfo, and the other (let's
say libc6/glibc) expects /usr/lib/terminfo. I remember that the
specific instructions in this bugfix/workaround were to do the
following or equivalent:
cd /usr/lib
ln -s ../share/terminfo ./terminfo
or:
ln -s /usr/share/terminfo /usr/lib/terminfo
So what this says is that the terminfo database/directory structure
can be accessed by either path. When something goes to reference
/usr/lib/terminfo, the symlink redirects it to essentially
/usr/share/terminfo, which is where it really resides on your
system. I personally prefer wherever possible to use relative
symlinks, because they still hold, more often than break, across
mount points, particularly NFS mounts, where the directory
structure may be different on the different systems.
Evidently the terminfo file moved between Red Hat 5.0 and 5.1, but Red
Hat did not include a link to let applications built prior to 5.1 find
it. Users reported that installing the link fixes the problem.
________________________________________________________________________
3.3.6. The Fullscreen File Transfer Display
[ [327]Top ] [ [328]Contents ] [ [329]Section Contents ] [
[330]Previous ]
Starting with ncurses versions dated 1998-12-12 (about a year before
ncurses 5.0), ncurses sets the terminal for buffered i/o, but
unfortunately is not able to restore it upon exit from curses (via
endwin()). Thus after a file transfer that uses the fullscreen file
transfer display, the terminal no longer echos nor responds
immediately to Tab, ?, and other special command characters. The same
thing happens on other platforms that use ncurses, e.g. FreeBSD.
Workarounds:
* Use SET XFER DISPLAY BRIEF, CRT, SERIAL, or NONE instead of
FULLSCREEN; or:
* Rebuild with KFLAGS=-DNONOSETBUF (C-Kermit 8.0)
In Red Hat 7.1, when using C-Kermit in a Gnome terminal window, it was
noticed that when the fullscreen file transfer display exits (via
endwin()), the previous (pre-file-transfer-display) screen is
restored. Thus you can't look at the completed display to see what
happened. This is a evidently a new feature of xterm. I can only
speculate that initscreen() and endwin() must send some kind of
special escape sequences that command xterm to save and restore the
screen. To defeat this effect, tell Linux you have a vt100 or other
xterm-compatible terminal that is not actually an xterm, or else tell
Kermit to SET TRANSFER DISPLAY to something besides FULLSCREEN.
________________________________________________________________________
3.4. C-KERMIT AND NEXTSTEP
[ [331]Top ] [ [332]Contents ] [ [333]Section Contents ] [ [334]Next ]
[ [335]Previous ]
Run C-Kermit in a Terminal, Stuart, or xterm window, or when logged in
remotely through a serial port or TELNET connection. C-Kermit does not
work correctly when invoked directly from the NeXTSTEP File Viewer or
Dock. This is because the terminal-oriented gtty, stty, & ioctl calls
don't work on the little window that NeXTSTEP pops up for non-NeXTSTEP
applications like Kermit. CBREAK and No-ECHO settings do not take
effect in the command parser -- commands are parsed strictly line at a
time. "set line /dev/cua" works. During CONNECT mode, the console
stays in cooked mode, so characters are not transmitted until carriage
return or linefeed is typed, and you can't escape back. If you want to
run Kermit directly from the File Viewer, then launch it from a shell
script that puts it in the desired kind of window, something like this
(for "Terminal"):
Terminal -Lines 24 -Columns 80 -WinLocX 100 -WinLocY 100 $FONT $FONTSIZE \
-SourceDotLogin -Shell /usr/local/bin/kermit &
C-Kermit does not work correctly on a NeXT with NeXTSTEP 3.0 to which
you have established an rlogin connection, due to a bug in NeXTSTEP
3.0, which has been reported to NeXT.
The SET CARRIER command has no effect on the NeXT -- this is a
limitation of the NeXTSTEP serial-port device drivers.
Hardware flow control on the NeXT is selected not by "set flow
rts/cts" in Kermit (since NeXTSTEP offers no API for this), but
rather, by using a specially-named driver for the serial device:
/dev/cufa instead /dev/cua; /dev/cufb instead of /dev/cub. This is
available only on 68040-based NeXT models (the situation for Intel
NeXTSTEP implementations is unknown).
NeXT-built 68030 and 68040 models have different kinds of serial
interfaces; the 68030 has a Macintosh-like RS-422 interface, which
lacks RTS and CTS signals; the 68040 has an RS-423 (RS-232 compatible)
interface, which supports the commonly-used modem signals. WARNING:
the connectors look exactly the same, but the pins are used in
completely DIFFERENT ways -- different cables are required for the two
kinds of interfaces.
IF YOU GET LOTS OF RETRANSMISSIONS during file transfer, even when
using a /dev/cuf* device and the modem is correctly configured for
RTS/CTS flow control, YOU PROBABLY HAVE THE WRONG KIND OF CABLE.
On the NeXT, Kermit reportedly (by TimeMon) causes the kernel to use a
lot of CPU time when using a "set line" connection. That's because
there is no DMA channel for the NeXT serial port, so the port must
interrupt the kernel for each character in or out.
One user reported trouble running C-Kermit on a NeXT from within
NeXT's Subprocess class under NeXTstep 3.0, and/or when rlogin'd from
one NeXT to another: Error opening /dev/tty:, congm: No such device or
address. Diagnosis: Bug in NeXTSTEP 3.0, cure unknown.
________________________________________________________________________
3.5. C-KERMIT AND QNX
[ [336]Top ] [ [337]Contents ] [ [338]Section Contents ] [ [339]Next ]
[ [340]Previous ]
See also: The [341]comp.os.qnx newsgroup.
Support for QNX 4.x was added in C-Kermit 5A(190). This is a
full-function implementation, thoroughly tested on QNX 4.21 and later,
and verified to work in both 16-bit and 32-bit versions. The 16-bit
version was dropped in C-Kermit 7.0 since it can no longer be built
successfully (after stripping most most features, I succeeded in
getting it to compile and link without complaint, but the executable
just beeps when you run it); for 16-bit QNX 4.2x, use C-Kermit 6.0 or
earlier, or else [342]G-Kermit.
The 32-bit version (and the 16-bit version prior to C-Kermit 7.0)
supports most of C-Kermit's advanced features including TCP/IP, high
serial speeds, hardware flow-control, modem-signal awareness, curses
support, etc.
BUG: In C-Kermit 6.0 on QNX 4.22 and earlier, the fullscreen file
transfer display worked fine the first time, but was fractured on
subsequent file transfers. Cause and cure unknown. In C-Kermit 7.0 and
QNX 4.25, this no longer occurs. It is not known if it would occur in
C-Kermit 7.0 or later on earlier QNX versions.
Dialout devices are normally /dev/ser1, /dev/ser2, ..., and can be
opened explicitly with SET LINE. Reportedly, "/dev/ser" (no unit
number) opens the first available /dev/sern device.
Like all other Unix C-Kermit implementations, QNX C-Kermit does not
provide any kind of terminal emulation. Terminal specific functions
are provided by your terminal, terminal window (e.g. QNX Terminal or
xterm), or emulator.
QNX C-Kermit, as distributed, does not include support for UUCP
line-locking; the QNX makefile entries (qnx32 and qnx16) include the
-DNOUUCP switch. This is because QNX, as distributed, does not include
UUCP, and its own communications software (e.g. qterm) does not use
UUCP line locking. If you have a UUCP product installed on your QNX
system, remove the -DNOUUCP switch from the makefile entry and
rebuild. Then check to see that Kermit's UUCP lockfile conventions are
the same as those of your UUCP package; if not, read the [343]UUCP
lockfile section of the [344]Installation Instructions and make the
necessary changes to the makefile entry (e.g. add -DHDBUUCP).
QNX does, however, allow a program to get the device open count. This
can not be a reliable form of locking unless all applications do it,
so by default, Kermit uses this information only for printing a
warning message such as:
C-Kermit>set line /dev/ser1
WARNING - "/dev/ser1" looks busy...
However, if you want to use it as a lock, you can do so with:
SET QNX-PORT-LOCK { ON, OFF }
This is OFF by default; if you set in ON, C-Kermit will fail to open
any dialout device when its open count indicates that another process
has it open. SHOW COMM (in QNX only) displays the setting, and if you
have a port open, it also shows the open count.
As of C-Kermit 8.0, C-Kermit's "open-count" form of line locking works
only in QNX4, not in QNX6 (this might change in a future C-Kermit
release).
________________________________________________________________________
3.6. C-KERMIT AND SCO
[ [345]Top ] [ [346]Contents ] [ [347]Section Contents ] [ [348]Next ]
[ [349]Previous ]
SECTION CONTENTS
3.6.1. [350]SCO XENIX
3.6.2. [351]SCO UNIX and OSR5
3.6.3. [352]Unixware
3.6.4. [353]Open UNIX 8
REFERENCES
* The comp.unix.sco.* newsgroups.
* [354]Section 3.10 below for Unixware.
* The following FAQs:
The comp.sco.misc FAQ:
[355]http://aplawrence.com/SCOFAQ/
Caldera (SCO) comp.unix.sco.programmer FAQ:
[356]http://www.zenez.com/cgi-bin/scoprogfaq/faq.pl
The UnixWare 7/OpenUNIX 8 FAQ:
[357]http://www.zenez.com/cgi-bin/scouw7faq/faq.pl
[358]http://zenez.pcunix.com/cgi-bin/scouw7faq/faq.pl
High Speed Modems for SCO Unix:
[359]http://pcunix.com/Unixart/modems.html
The UnixWare FAQ
[360]http://www.freebird.org/faq/
The UnixWare 1.x and 2.0 Programmer FAQ
[361]http://www.freebird.org/faq/developer.html
Caldera Support Knowledge Base
[362]http://support.caldera.com/caldera
[363]http://stage.caldera.com/ta/
Caldera (SCO) Technical Article Search Center
[364]http://aplawrence.com/newtosco.html
New to SCO (Tony Lawrence)
The same comments regarding terminal emulation and key mapping apply
to SCO operating systems as to all other Unixes. C-Kermit is not a
terminal emulator, and you can't use it to map F-keys, Arrow keys,
etc. The way to do this is with xmodmap (xterm) or loadkeys (console).
For a brief explanation, see [365]Section 3.0.5. For a fuller
explanation, [366]ClICK HERE.
Also see general comments on PC-based Unixes in [367]Section 3.0.
3.6.1. SCO XENIX
[ [368]Top ] [ [369]Contents ] [ [370]Section Contents ] [ [371]Next ]
Old Xenix versions... Did you know: Xenix 3.0 is *older* than Xenix
2.0?
In Xenix 2.3.4 and probably other Xenix versions, momentarily dropping
DTR to hang up a modem does not work. DTR goes down but does not come
up again. Workaround: Use SET MODEM HANGUP-METHOD MODEM-COMMAND.
Anybody who would like to fix this is welcome to take a look at
tthang() in [372]ckutio.c. Also: modem signals can not be read in
Xenix, and the maximum serial speed is 38400.
There is all sorts of confusion among SCO versions, particularly when
third- party communications boards and drivers are installed,
regarding lockfile naming conventions, as well as basic functionality.
As far as lockfiles go, all bets are off if you are using a
third-party multiport board. At least you have the source code.
Hopefully you also have a C compiler :-)
Xenix 2.3.0 and later claim to support RTSFLOW and CTSFLOW, but this
is not modern bidirectional hardware flow control; rather it
implements the original RS-232 meanings of these signals for
unidirectional half-duplex line access: If both RTSFLOW and CTSFLOW
bits are set, Xenix asserts RTS when it wants to send data and waits
for CTS assertion before it actually starts sending data (also,
reportedly, even this is broken in Xenix 2.3.0 and 2.3.1).
________________________________________________________________________
3.6.2. SCO UNIX AND OSR5
[ [373]Top ] [ [374]Contents ] [ [375]Section Contents ] [ [376]Next ]
[ [377]Previous ]
SCO systems tend to use different names (i.e. drivers) for the same
device. Typically /dev/tty1a refers to a terminal device that has no
modem control; open, read, write, and close operations do not depend
on carrier. On the other hand, /dev/tty1A (same name, but with final
letter upper case), is the same device with modem control, in which
carrier is required (the SET LINE command does not complete until
carrier appears, read/write operations fail if there is no carrier,
etc).
SCO OpenServer 5.0.5 and earlier do not support the reading of modem
signals. Thus "show comm" does not list modem signals, and C-Kermit
does not automatically pop back to its prompt when the modem hangs up
the connection (drops CD). The ioctl() call for this is simply not
implmented, at least not in the standard drivers. OSR5.0.6 attempts to
deal with modem signals but fails; however OSR5.0.6a appears to
function properly.
Dialing is likely not to work well in SCO OpenServer 5.0.x because
many of the serial-port APIs simply do not operate when using the
standard drivers. For example, if DTR is dropped by the recommended
method (setting speed to 0 for half a seconds, then restoring the
speed), DTR and RTS go down but never come back up. When in doubt SET
MODEM HANGUP-METHOD MODEM-COMMAND or SET DIAL HANGUP OFF.
On the other hand, certain functions that might not (do not) work
right or at all when using SCO drivers (e.g. high serial speeds,
hardware flow control, and/or reading of modem signals) might work
right when using third-party drivers. (Example: hardware flow control
works, reportedly, only on uppercase device like tty1A -- not tty1a --
and only when CLOCAL is clear when using the SCO sio driver, but there
are no such restrictions in, e.g., [378]Digiboard drivers).
One user reports that he can't transfer large files with C-Kermit
under SCO OSR5.0.0 and 5.0.4 -- after the first 5K, everything falls
apart. Same thing without Kermit -- e.g. with ftp over a PPP
connection. Later, he said that replacing SCO's SIO driver with FAS,
an alternative communications driver, made the problem go away:
[379]ftp://ftp.fu-berlin.de/pub/unix/driver/fas
With regard to bidirectional serial ports on OpenServer 5.0.4, the
following advice appeared on an SCO-related newsgroup:
No amount of configuration information is going to help you on
5.0.4 unless it includes the kludge for the primary problem. With
almost every modem, the 5.0.4 getty will barf messages and may or
may not connect. There are 2 solutions and only one works on 5.0.4.
Get the atdialer binary from a 5.0.0 system and substitute it for
the native 5.0.4 atdialer. The other solution is to upgrade to
5.0.5. And, most of all, on any OpenServer products, do NOT run the
badly broken Modem Manager. Configure the modems in the time
honored way that dates back to Xenix.
Use SCO-provided utilities for switching the directionality of a modem
line, such as "enable" and "disable" commands. For example, to dial
out on tty1a, which is normally set up for logins:
disable tty1a
kermit -l /dev/tty1a
enable tty1a
If a tty device is listed as an ACU in /usr/lib/uucp/Devices and is
enabled, getty resets the ownership and permissions to uucp.uucp and
640 every time the device is released. If you want to use the device
only for dialout, and you want to specify other owners or permissions,
you should disable it in /usr/lib/uucp/Devices; this will prevent
getty from doing things to it. You should also changes the device's
file modes in /etc/conf/node.d/sio by changing fields 5-7 for the
desired device(s); this determines how the devices are set if you
relink the kernel.
One SCO user of C-Kermit 5A(190) reported that only one copy of Kermit
can run at a time when a Stallion Technologies multiport boards are
installed. Cause, cure, and present status unknown (see [380]Section
14 for more info regarding Stallion).
Prior to SCO OpenServer 5.0.4, the highest serial port speed supported
by SCO was 38400. However, in some SCO versions (e.g. OSR5) it is
possible to map rarely-used lower speeds (like 600 and 1800) to higher
ones like 57600 and 115200. To find out how, go to
[381]http://www.sco.com/ and search for "115200". In OSR5.0.4, serial
speeds up to 921600 are supported through the POSIX interface;
C-Kermit 6.1.193 or later, when built for OSR5.0.4 using /bin/cc (NOT
the UDK, which hides the high-speed definitions from CPP), supports
these speeds, but you might be able to run this binary on earlier
releases to get the high serial speeds, depending on various factors,
described by Bela Lubkin of SCO:
Serial speeds under SCO Unix / Open Desktop / OpenServer
========================================================
Third party drivers (intelligent serial boards) may provide any speeds
they desire; most support up to 115.2Kbps.
SCO's "sio" driver, which is used to drive standard serial ports with
8250/16450/16550 and similar UARTs, was limited to 38400bps in older
releases. Support for rates through 115.2Kbps was added in the
following releases:
SCO OpenServer Release 5.0.0 (requires supplement "rs40b")
SCO OpenServer Release 5.0.2 (requires supplement "rs40a" or "rs40b")
SCO OpenServer Release 5.0.4 or later
SCO Internet FastStart Release 1.0.0 or later
SCO supplements are at [382]ftp://ftp.sco.com/; the "rs40" series are
under directory /Supplements/internet
Kermit includes the high serial speeds in all OSR5 builds, but that
does not necessarily mean they work. For example, on our in-house
5.0.5 system, SET SPEED 57600 or higher seems to succeed (no error
occurs) but when we read the speed back the driver says it is 50.
Similarly, 76800 becomes 75, and 115200 becomes 110. Testing shows the
resulting speed is indeed the low one we read back, not the high one
we asked for. Moral: Use speeds higher than 38400 with caution on SCO
OSR5.
Reportedly, if you have a script that makes a TCP/IP SET HOST (e.g.
Telnet) connection to SCO 3.2v4.2 with TCP/IP 1.2.1, and then does the
following:
script $ exit
hangup
this causes a pseudoterminal (pty) to be consumed on the SCO system;
if you do it enough times, it will run out of ptys. An "exit" command
is being sent to the SCO shell, and a HANGUP command is executed
locally, so the chances are good that both sides are trying to close
the connection at once, perhaps inducing a race condition in which the
remote pty is not released. It was speculated that this would be fixed
by applying SLS net382e, but it did not. Meanwhile, the workaround is
to insert a "pause" between the SCRIPT and HANGUP commands. (The
situation with later SCO releases is not known.)
SCO UNIX and OpenServer allow their console and/or terminal drivers to
be configured to translate character sets for you. DON'T DO THIS WHEN
USING KERMIT! First of all, you don't need it -- Kermit itself already
does this for you. And second, it will (a) probably ruin the
formatting of your screens (depending on which emulation you are
using); and (b) interfere with all sorts of other things -- legibility
of non-ASCII text on the terminal screen, file transfer, etc. Use:
mapchan -n
to turn off this feature.
Note that there is a multitude of SCO entries in the makefile, many of
them exhibiting an unusually large number of compiler options. Some
people actually understand all of this. Reportedly, things are
settling down with SCO OpenServer 5.x and Unixware 7 (and Open UNIX 8
and who knows what the next one will be -- Linux probably) -- the SCO
UDK compiler is said to generate binaries that will run on either
platform, by default, automatically. When using gcc or egcs, on the
other hand, differences persist, plus issues regarding the type of
binary that is generated (COFF, ELF, etc), and where and how it can
run. All of this could stand further clarification by SCO experts.
________________________________________________________________________
3.6.3. Unixware
[ [383]Top ] [ [384]Contents ] [ [385]Section Contents ] [ [386]Next ]
[ [387]Previous ]
Unixware changed hands several times before landing at SCO, and so has
its [388]own section in this document. (Briefly: AT&T UNIX Systems
Laboratories sold the rights to the UNIX name and to System V R4 (or
R5?) to Novell; later Novell spun its UNIX division off into a new
company called Univel, which eventually was bought by SCO, which later
was bought by Caldera, which later sort of semi-spun-off SCO...)
________________________________________________________________________
3.6.4. Open UNIX 8
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[392]Previous ]
SCO was bought by Caldera in 2000 or 2001 and evolved Unixware 7.1
into Caldera Open UNIX 8.00. It's just like Unixware 7.1 as far as
Kermit is concerned (the Unixware 7.1 makefile target works for Open
UNIX 8.00, and in fact a Unixware 7.1 Kermit binary built on Unixware
7.1 runs under OU8; a separate OU8 makefile target exists simply to
generate an appropriate program startup herald). Open Unix is now
defunct; subsequent releases are called UnixWare again (e.g. UnixWare
7.1.3).
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3.7. C-KERMIT AND SOLARIS
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[ [397]Previous ]
SECTION CONTENTS
3.7.1. [398]Serial Port Configuration
3.7.2. [399]Serial Port Problems
3.7.3. [400]SunLink X.25
3.7.4. [401]Sun Workstation Keyboard Mapping
3.7.5. [402]Solaris 2.4 and Earlier
REFERENCES
* The [403]comp.unix.solaris newsgroup
* [404]http://access1.sun.com/
* [405]http://docs.sun.com/
* [406]http://www.sunhelp.com/
* [407]http://www.wins.uva.nl/pub/solaris/solaris2/
* [408]http://www.wins.uva.nl/cgi-bin/sfaq.cgi
* [409]ftp://ftp.wins.uva.nl/pub/solaris
* [410]http://www.science.uva.nl/pub/solaris/solaris2.html
And about serial communications in particular, see "Celeste's Tutorial
on Solaris 2.x Modems and Terminals":
[411]http://www.stokely.com/
In particular:
[412]http://www.stokely.com/unix.sysadm.resources/faqs.sun.html
For PC-based Solaris, also see general comments on PC-based Unixes in
[413]Section 3.0. Don't expect Solaris or any other kind of Unix to
work right on a PC until you resolve all interrupt conflicts. Don't
expect to be able to use COM3 or COM4 (or even COM2) until you have
configured their addresses and interrupts.
________________________________________________________________________
3.7.1. Serial Port Configuration
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[417]Section Contents ] [ [418]Next ]
Your serial port can't be used -- or at least won't work right --
until it is enabled in Solaris. For example, you get a message like
"SERIAL: Operation would block" when attempting to dial. This probably
indicates that the serial port has not been enabled for use with
modems. You'll need to follow the instructions in your system setup or
management manual, such as (e.g.) the Desktop SPARC Sun System &
Network Manager's Guide, which should contain a section "Setting up
Modem Software"; read it and follow the instructions. These might (or
might not) include running a program called "eeprom", editing some
system configuration file (such as, for example:
/platform/i86pc/kernel/drv/asy.conf
and then doing a configuration reboot, or running some other programs
like drvconfig and devlinks. "man eeprom" for details.
Also, on certain Sun models like IPC, the serial port hardware might
need to have a jumper changed to make it an RS-232 port rather than
RS-423.
eeprom applies only to real serial ports, not to "Spiff" devices
(serial port expander), in which case setup with Solaris' admintool is
required.
Another command you might need to use is pmadm, e.g.:
pmadm -d -p zsmon -s tty3
pmadm -e -p zsmon -s tty3
You can use the following command to check if a process has the device
open:
fuser -f /dev/term/3
In some cases, however (according to Sun support, May 2001) "It is
still possible that a zombie process has hold of the port EVEN IF
there is no lock file and the fuser command comes up empty. In that
case, the only way to resolve the problem is by rebooting."
If you can't establish communication through a serial port to a device
that is not asserting CD (Carrier Detect), try setting the environment
variable "ttya-ignore-cd" to "true" (replace "ttya" with the port
name).
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3.7.2. Serial Port Problems
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[ [423]Previous ]
Current advice from Sun is to always the /dev/cua/x devices for
dialing out, rather than the /dev/term/x. Nevertheless, if you have
trouble dialing out with one, try the other.
Reportedly, if you start C-Kermit and "set line" to a port that has a
modem connected to it that is not turned on, and then "set flow
rts/cts", there might be some (unspecified) difficulties closing the
device because the CTS signal is not coming in from the modem.
________________________________________________________________________
3.7.3. SunLink X.25
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[ [428]Previous ]
The built-in SunLink X.25 support for Solaris 2.3/2.4./25 and SunLink
8.01 or 9.00 works OK provided the X.25 system has been installed and
initialized properly. Packet sizes might need to be reduced to 256,
maybe even less, depending on the configuration of the X.25
installation. On one connection where C-Kermit 6.0 was tested, very
large packets and window sizes could be used in one direction, but
only very small ones would work in the other.
In any case, according to Sun, C-Kermit's X.25 support is superfluous
with SunLink 8.x / Solaris 2.3. Quoting an anonymous Sun engineer:
... there is now no need to include any X.25 code within kermit. As
of X.25 8.0.1 we support the use of kermit, uucp and similar
protocols over devices of type /dev/xty. This facility was there in
8.0, and should also work on the 8.0 release if patch 101524 is
applied, but I'm not 100% sure it will work in all cases, which is
why we only claim support from 8.0.1 onwards.
When configuring X.25, on the "Advanced Configuration->Parameters"
screen of the x25tool you can select a number of XTY devices. If
you set this to be > 1, press Apply, and reboot, you will get a
number of /dev/xty entries created.
Ignore /dev/xty0, it is a special case. All the others can be used
exactly as if they were a serial line (e.g. /dev/tty) connected to
a modem, except that instead of using Hayes-style commands, you use
PAD commands.
From kermit you can do a 'set line' command to, say, /dev/xty1,
then set your dialing command to be "CALL 12345678", etc. All the
usual PAD commands will work (SET, PAR, etc).
I know of one customer in Australia who is successfully using this,
with kermit scripts, to manage some X.25-connected switches. He
used standard kermit, compiled for Solaris 2, with X.25 8.0 xty
devices.
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3.7.4. Sun Workstation Keyboard Mapping
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[ [433]Previous ]
Hints for using a Sun workstation keyboard for VT emulation when
accessing VMS, from the [434]comp.os.vms newsgroup:
From: Jerry Leichter <leichter@smarts.com>
Newsgroups: comp.os.vms
Subject: Re: VT100 keyboard mapping to Sun X server
Date: Mon, 19 Aug 1996 12:44:21 -0400
> I am stuck right now using a Sun keyboard (type 5) on systems
running SunOS
> and Solaris. I would like to use EVE on an OpenVMS box with
display back to
> the Sun. Does anyone know of a keyboard mapping (or some other
procedure)
> which will allow the Sun keyboard to approximate a VT100/VT220?
You can't get it exactly - because the keypad has one fewer key -
but you can come pretty close. Here's a set of keydefs I use:
keycode 101=KP_0
keycode 119=KP_1
keycode 120=KP_2
keycode 121=KP_3
keycode 98=KP_4
keycode 99=KP_5
keycode 100=KP_6
keycode 75=KP_7
keycode 76=KP_8
keycode 77=KP_9
keycode 52=KP_F1
keycode 53=KP_F2
keycode 54=KP_F3
keycode 57=KP_Decimal
keycode 28=Left
keycode 29=Right
keycode 30=KP_Separator
keycode 105=KP_F4
keycode 78=KP_Subtract
keycode 8=Left
keycode 10=Right
keycode 32=Up
keycode 33=Down
keycode 97=KP_Enter
Put this in a file - I use "keydefs" in my home directory and feed
it into xmodmap:
xmodmap - <$HOME/keydefs
This takes care of the arrow keys and the "calculator" key cluster.
The "+" key will play the role of the DEC "," key. The Sun "-" key
will be like the DEC "-" key, though it's in a physically different
position - where the DEC PF4 key is. The PF4 key is ... damn, I'm
not sure where "key 105" is. I *think* it may be on the leftmost
key of the group of four just above the "calculator" key cluster.
I also execute the following (this is all in my xinitrc file):
xmodmap -e 'keysym KP_Decimal = KP_Decimal'
xmodmap -e 'keysym BackSpace = Delete BackSpace' \
-e 'keysym Delete = BackSpace Delete'
xmodmap -e 'keysym KP_Decimal = Delete Delete KP_Decimal'
xmodmap -e 'add mod1 = Meta_R'
xmodmap -e 'add mod1 = Meta_L'
Beware of one thing about xmodmap: Keymap changes are applied to
the *whole workstation*, not just to individual windows. There is,
in fact, no way I know of to apply them to individual windows.
These definitions *may* confuse some Unix programs (and/or some
Unix users).
If you're using Motif, you may also need to apply bindings at the
Motif level. If just using xmodmap doesn't work, I can try and dig
that stuff up for you.
________________________________________________________________________
3.7.5. Solaris PPP Connections
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[ [439]Previous ]
The following is a report from a user of C-Kermit 8.0 on Solaris 8 and
9, who had complained that while Kermit file transfers worked
perfectly on direct (non-PPP) dialout connections, they failed
miserably on PPP connections. We suggested that the PPP dialer
probably was not setting the port and/or modem up in the same way that
Kermit did:
I want to get back on this and tell you what the resolution was.
You pointed me in the direction of flow control, which turned out
to be the key.
Some discussion on the comp.unix.solaris newsgroup led to some
comments from Greg Andrews about the need to use the uucp driver to
talk to the modem (/dev/cua/a). I had to remind Greg that no matter
what the manpages for the zs and se drivers say, the ppp that Sun
released with Solaris 8 7/01, and has in Solaris 9, is a setuid
root program, and simply trying to make a pppd call from user space
specifying /dev/cua/a would fail because of permissions. Greg
finally put the question to the ppp people, who came back with
information that is not laid out anywhere in the docs available for
Solaris users. Namely, put /dev/cua/a in one of the priviledged
options files in the /etc/ppp directory. That, plus resetting the
OBP ttya-ignore-cd flag (this is Sun hardware) to false, seems to
have solved the problems.
While I note that I had installed Kermit suid to uucp to use
/dev/cua/a on this particular box, it seems to run fine through
/dev/term/a. Not so with pppd.
With this change in place, I seem to be able to upload and download
through telnet run on Kermit with the maximum length packets. I
note that the window allocation display does show STREAMING, using
telnet. Running ssh on Kermit, I see the standard 1 of 30 windows
display, and note that there appears to be a buffer length limit
between 1000 and 2000 bytes. Run with 1000, and it's tick-tock,
solid as a rock. With 2000 I see timeout errors and RTS/CTS action
on the modem.
Kermit's packet-length and other controls let you make adjustments
like this to get around whatever obstacles might be thrown up -- in
this case (running Kermit over ssh), the underling Solaris PTY driver.
________________________________________________________________________
3.7.6. Solaris 2.4 and Earlier
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[443]Previous ]
C-Kermit can't be compiled successfully under Solaris 2.3 using
SUNWspro cc 2.0.1 unless at least some of the following patches are
applied to cc (it is not known which one(s), if any, fix the problem):
* 100935-01 SparcCompiler C 2.0.1: bad code generated when addresses
of two double arguments are involved
* 100961-05 SPARCcompilers C 2.0.1: conditional expression with
function returning structure gives wrong value
* 100974-01 SparcWorks 2.0.1: dbx jumbo patch
* 101424-01 SPARCworks 2.0.1 maketool SEGV's instantly on Solaris
2.3
With unpatched cc 2.0.1, the symptom is that certain modules generate
truncated object files, resulting in many unresolved references at
link time.
The rest of the problems in this section have to do with
bidirectional terminal ports and the Solaris Port Monitor. A bug in
C-Kermit 5A ticked a bug in Solaris. The C-Kermit bug was fixed in
version 6.0, and the Solaris bug was fixed in 2.4 (I think, or
maybe 2.5).
Reportedly, "C-Kermit ... causes a SPARCstation running Solaris 2.3 to
panic after the modem connects. I have tried compiling C-Kermit with
Sun's unbundled C compiler, with GCC Versions 2.4.5 and 2.5.3, with
make targets 'sunos51', 'sunos51tcp', 'sunos51gcc', and even 'sys5r4',
and each time it compiles and starts up cleanly, but without fail, as
soon as I dial the number and get a 'CONNECT' message from the modem,
I get:
BAD TRAP
kermit: Data fault
kernel read fault at addr=0x45c, pme=0x0
Sync Error Reg 80 <INVALID>
...
panic: Data Fault.
...
Rebooting...
The same modem works fine for UUCP/tip calling." Also (reportedly),
this only happens if the dialout port is configured as in/out via
admintool. If it is configured as out-only, no problem. This is the
same dialing code that works on hundreds of other System-V based Unix
OS's. Since it should be impossible for a user program to crash the
operating system, this problem must be chalked up to a Solaris bug.
Even if you SET CARRIER OFF, CONNECT, and dial manually by typing
ATDTnnnnnnn, the system panics as soon as the modem issues its CONNECT
message. (Clearly, when you are dialing manually, C-Kermit does not
know a thing about the CONNECT message, and so the panic is almost
certainly caused by the transition of the Carrier Detect (CD) line
from off to on.) This problem was reported by many users, all of whom
say that C-Kermit worked fine on Solaris 2.1 and 2.2. If the
speculation about CD is true, then a possible workaround might be to
configure the modem to leave CD on (or off) all the time. Perhaps by
the time you read this, a patch will have been issued for Solaris 2.3.
The following is from Karl S. Marsh, Systems & Networks Administrator,
AMBIX Systems Corp, Rochester, NY:
Environment: Solaris 2.3 Patch 101318-45 C-Kermit 5A(189) (and
presumably this applies to 188 and 190 also). eeprom setting:
ttya-rts-dtr-off=false
ttya-ignore-cd=false
ttya-mode=19200,8,n,8,-
To use C-Kermit on a bidirectional port in this environment, do not
use admintool to configure the port. Use admintool to delete any
services running on the port and then quit admintool and issue the
following command:
pmadm -a -p zsmon -s ttyb -i root -fu -v 1 -m "`ttyadm -b -d /dev/term/b \
-l conttyH -m ldterm,ttcompat -s /usr/bin/login -S n`"
[NOTE: This was copied from a blurry fax, so please check it
carefully] where:
-a = Add service
-p = pmtag (zsmon)
-s = service tag (ttyb)
-i = id to be associated with service tag (root)
-fu = create utmp entry
-v = version of ttyadm
-m = port monitor-specific portion of the port monitor administrative file
entry for the service
-b = set up port for bidirectional use
-d = full path name of device
-l = which ttylabel in the /etc/ttydefs file to use
-m = a list of pushable STREAMS modules
-s = pathname of service to be invoked when connection request received
-S = software carrier detect on or off (n = off)
"This is exactly how I was able to get Kermit to work on a
bi-directional port without crashing the system."
On the Solaris problem, also see SunSolve Bug ID 1150457 ("Using
C-Kermit, get Bad Trap on receiving prompt from remote system").
Another user reported "So, I have communicated with the Sun tech
support person that submitted this bug report [1150457]. Apparently,
this bug was fixed under one of the jumbo kernel patches. It would
seem that the fix did not live on into 101318-45, as this is EXACTLY
the error that I see when I attempt to use kermit on my system."
Later (Aug 94)... C-Kermit dialout successfully tested on a Sun4m with
a heavily patched Solaris 2.3. The patches most likely to have been
relevant:
* 101318-50: SunOS 5.3: Jumbo patch for kernel (includes libc,
lockd)
* 101720-01: SunOS 5.3: ttymon - prompt not always visible on a
modem connection
* 101815-01: SunOS 5.3: Data fault in put() NULL queue passed from
ttycommon_qfull()
* 101328-01: SunOS 5.3: Automation script to properly setup tty
ports prior to PCTS execution
Still later (Nov 94): another user (Bo Kullmar in Sweden) reports that
after using C-Kermit to dial out on a bidirectional port, the port
might not answer subsequent incoming calls, and says "the problem is
easy enough to fix with the Serial Port Manager; I just delete the
service and install it again using the graphical interface, which
underneath uses commands like sacadm and pmadm." Later Bo reports, "I
have found that if I run Kermit with the following script then it
works. This script is for /dev/cua/a, "-s a" is the last a in
/dev/cua/a:
#! /bin/sh
kermit
sleep 2
surun pmadm -e -p zsmon -s a
________________________________________________________________________
3.8. C-KERMIT AND SUNOS
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[ [448]Previous ]
For additional information, see "Celeste's Tutorial on SunOS 4.1.3+
Modems and Terminals":
[449]http://www.stokely.com/
For FAQs, etc, from Sun, see:
* [450]http://access1.sun.com/
For history of Sun models and SunOS versions, see (should be all the
same):
* [451]http://www.ludd.luth.se/~bear/project/sun/sun.hardware.txt
* [452]ftp://ftp.netcom.com/pub/ru/rubicon/sun.hdwr.ref
* [453]ftp://ftp.intnet.net/pub/SUN/Sun-Hardware-Ref
Sun SPARCstation users should read the section "Setting up Modem
Software" in the Desktop SPARC Sun System & Network Manager's Guide.
If you don't set up your serial ports correctly, Kermit (and other
communications software) won't work right.
Also, on certain Sun models like IPC, the serial port hardware might
need to have a jumper changed to make it an RS-232 port rather than
RS-423.
Reportedly, C-Kermit does not work correctly on a Sun SPARCstation in
an Open Windows window with scrolling enabled. Disable scrolling, or
else invoke Kermit in a terminal emulation window (xterm, crttool,
vttool) under SunView (this might be fixed in later SunOS releases).
On the Sun with Open Windows, an additional symptom has been reported:
outbound SunLink X.25 connections "magically" translate CR typed at
the keyboard into LF before transmission to the remote host. This
doesn't happen under SunView.
SET CARRIER ON, when used on the SunOS 4.1 version of C-Kermit
(compiled in the BSD universe), causes the program to hang
uninterruptibly when SET LINE is issued for a device that is not
asserting carrier. When Kermit is built in the Sys V universe on the
same computer, there is no problem (it can be interrupted with
Ctrl-C). This is apparently a limitation of the BSD-style tty driver.
SunOS 4.1 C-Kermit has been observed to dump core when running a
complicated script program under cron. The dump invariably occurs in
ttoc(), while trying to output a character to a TCP/IP TELNET
connection. ttoc() contains a write() call, and when the system or the
network is very busy, the write() call can get stuck for long periods
of time. To break out of deadlocks caused by stuck write() calls,
there is an alarm around the write(). It is possible that the core
dump occurs when this alarm signal is caught. (This one has not been
observed recently -- possibly fixed in edit 190.)
On Sun computers with SunOS 4.0 or 4.1, SET FLOW RTS/CTS works only if
the carrier signal is present from the communication device at the
time when C-Kermit enters packet mode or CONNECT mode. If carrier is
not sensed (e.g. when dialing), C-Kermit does not attempt to turn on
RTS/CTS flow control. This is because the SunOS serial device driver
does not allow characters to be output if RTS/CTS is set (CRTSCTS) but
carrier (and DSR) are not present. Workaround (maybe): SET CARRIER OFF
before giving the SET LINE command, establish the connection, then SET
FLOW RTS/CTS
It has also been reported that RTS/CTS flow control under SunOS 4.1
through 4.1.3 works only on INPUT, not on output, and that there is a
patch from Sun to correct this problem: Patch-ID# T100513-04, 20 July
1993 (this patch might apply only to SunOS 4.1.3). It might also be
necessary to configure the eeprom parameters of the serial port; e.g.
do the following as root at the shell prompt:
eeprom ttya-ignore-cd=false
eeprom ttya-rts-dtr-off=true
There have been reports of file transfer failures on Sun-3 systems
when using long packets and/or large window sizes. One user says that
when this happens, the console issues many copies of this message:
chaos vmunix: zs1: ring buffer overflow
This means that SunOS is not scheduling Kermit frequently enough to
service interrupts from the zs serial device (Zilog 8350 SCC serial
communication port) before its input silo overflows. Workaround: use
smaller packets and/or a smaller window size, or use "nice" to
increase Kermit's priority. Use hardware flow control if available, or
remove other active processes before running Kermit.
SunLink X.25 support in C-Kermit 5A(190) was built and tested
successfully under SunOS 4.1.3b and SunLink X.25 7.00.
________________________________________________________________________
3.9. C-KERMIT AND ULTRIX
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[ [458]Previous ]
See also: The [459]comp.unix.ultrix and [460]comp.sys.dec newsgroups.
There is no hardware flow control in Ultrix. That's not a Kermit
deficiency, but an Ultrix one.
When sending files to C-Kermit on a Telnet connection to a remote
Ultrix system, you must SET PREFIXING ALL (or at least prefix more
control characters than are selected by SET PREFIXING CAUTIOUS).
Reportedly, DEC ULTRIX 4.3 is immune to C-Kermit's disabling of
SIGQUIT, which is the signal that is generated when the user types
Ctrl-\, which kills the current process (i.e. C-Kermit) and dumps
core. Diagnosis and cure unknown. Workaround: before starting C-Kermit
-- or for that matter, when you first log in because this applies to
all processes, not just Kermit -- give the following Unix command:
stty quit undef
Certain operations driven by RS-232 modem signal do not work on
DECstations or other DEC platforms whose serial interfaces use MMP
connectors (DEC version of RJ45 telephone jack with offset tab). These
connectors convey only the DSR and DTR modem signals, but not carrier
(CD), RTS, CTS, or RI. Use SET CARRIER OFF to enable communication, or
"hotwire" DSR to CD.
The maximum serial speed on the DECstation 5000 is normally 19200, but
various tricks are available (outside Kermit) to enable higher rates.
For example, on the 5000/200, 19200 can be remapped (somehow,
something to do with "a bit in the SIR", whatever that is) to 38400,
but in software you must still refer to this speed as 19200; you can't
have 19200 and 38400 available at the same time.
19200, reportedly, is also the highest speed supported by Ultrix, but
NetBSD reportedly supports speeds up to 57600 on the DECstation,
although whether and how well this works is another question.
In any case, given the lack of hardware flow control in Ultrix, high
serial speeds are problematic at best.
________________________________________________________________________
3.10. C-KERMIT AND UNIXWARE
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[ [465]Previous ]
See also:
* The Freebird Project (Unixware software repository)
[466]http://www.freebird.org/
* The UnixWare FAQ: [467]http://www.freebird.org/faq/
* The following newsgroups:
+ [468]comp.unix.unixware.misc
+ [469]comp.unix.sco.misc.
Also see general comments on PC-based Unixes in [470]Section 3.0. By
the way, this section is separate from the SCO (Caldera) section
because at the time this section was started, Unixware was owned by a
company called Univel. Later it was sold to Novell, and then to SCO.
Still later, SCO was sold to Caldera.
In Unixware 2.0 and later, the preferred serial device names (drivers)
are /dev/term/00 (etc), rather than /dev/tty00 (etc). Note the
following correspondence of device names and driver characteristics:
New name Old name Description
/dev/term/00 /dev/tty00 ???
/dev/term/00h /dev/tty00h Modem signals and hardware flow control
/dev/term/00m /dev/tty00m Modem signals(?)
/dev/term/00s /dev/tty00s Modem signals and software flow control
/dev/term/00t /dev/tty00t ???
Lockfile names use device.major.minor numbers, e.g.:
/var/spool/locks/LK.7679.003.005
The minor number varies according to the device name suffix (none, h,
m, s, or t). Only the device and major number are compared, and thus
all of the different names for the same physical device (e.g. all of
those shown in the table above) interlock effectively.
Prior to UnixWare 7, serial speeds higher than 38400 are not
supported. In UnixWare 7, we also support 57600 and 115200, plus some
unexpected ones like 14400, 28800, and 76800, by virtue of a strange
new interface, evidently peculiar to UnixWare 7, discovered while
digging through the header files: tcsetspeed(). Access to this
interface is allowed only in POSIX builds, and thus the UnixWare 7
version of C-Kermit is POSIX-based, unlike C-Kermit for Unixware 1.x
and 2.x (since the earlier UnixWare versions did not support high
serial speeds, period).
HOWEVER, turning on POSIX features engages all of the "#if
(!_POSIX_SOURCE)" clauses in the UnixWare header files, which in turn
prevent us from having modem signals, access to the hardware flow
control APIs, select(), etc -- in short, all the other things we need
in communications software, especially when high speeds are used. Oh
the irony. And so C-Kermit must be shamelessly butchered -- as it has
been so many times before -- to allow us to have the needed features
from the POSIX and non-POSIX worlds. See the UNIXWAREPOSIX sections of
[471]ckutio.c.
After the butchery, we wind up with Unixware 2.x having full
modem-signal capability, but politically-correct Unixware 7.x lacking
the ability to automatically detect a broken connection when carrier
drops.
Meanwhile the Unixware tcsetspeed() function allows any number at all
(any long, 0 or positive) as an argument and succeeds if the number is
a legal bit rate for the serial device, and fails otherwise. There is
no list anywhere of legal speeds. Thus the SET SPEED keyword table
("set speed ?" to see it) is hardwired based on trial and error with
all known serial speeds, the maximum being 115200. However, to allow
for the possibility that other speeds might be allowed in the future
(or with different port drivers), the SET SPEED command for UnixWare 7
only allows you to specify any number at all; a warning is printed if
the number is not in the list, but the number is accepted anyway; the
command succeeds if tcsetspeed() accepts the number, and fails
otherwise.
In C-Kermit 8.0 testing, it was noticed that the POSIX method for
hanging up the phone by dropping DTR (set speed 0, pause, restore
speed) did not actually drop DTR. The APIs do not return any error
indication, but nothing happens. I changed tthang() to skip the
special case I had made for Unixware and instead follow the normal
path: if TIOCSDTR is defined use that, otherwise blah blah... It turns
out TIOCSDTR *is* defined, and it works.
So in Unixware (at least in 2.1.3) we can read modem signals, hangup
by toggling DTR, and so on, BUT... But once the remote hangs up and
Carrier drops, the API for reading modem signals ceases to function;
although the device is still open, the TIOCMGET ioctl always raises
errno 6 = ENXIO, "No such device or address".
Old business:
Using C-Kermit 6.0 on the UnixWare 1.1 Application Server, one user
reported a system panic when the following script program is executed:
set line /dev/tty4
set speed 9600
output \13
connect
The panic does not happen if a PAUSE is inserted:
set line /dev/tty4
set speed 9600
pause 1
output \13
connect
This is using a Stallion EasyIO card installed as board 0 on IRQ 12 on
a Gateway 386 with the Stallion-supplied driver. The problem was
reported to Novell and Stallion and (reportedly) is now fixed.
________________________________________________________________________
3.11. C-KERMIT AND APOLLO SR10
[ [472]Top ] [ [473]Contents ] [ [474]Section Contents ] [ [475]Next ]
[ [476]Previous ]
Reportedly, version 5A(190), when built under Apollo SR10 using "make
sr10-bsd", compiles, links, and executes OK, but leaves the terminal
unusable after it exits -- the "cs7" or "cs8" (character size)
parameter has become cs5. The terminal must be reset from another
terminal. Cause and cure unknown. Suggested workaround: Wrap Kermit in
a shell script something like:
kermit @*
stty sane
________________________________________________________________________
3.12. C-KERMIT AND TANDY XENIX 3.0
[ [477]Top ] [ [478]Contents ] [ [479]Section Contents ] [ [480]Next ]
[ [481]Previous ]
C-Kermit 7.0 was too big to be built on Tandy Xenix, even in a minimum
configuration; version 6.0 is the last one that fits.
Reportedly, in C-Kermit 6.0, if you type lots of Ctrl-C's during
execution of the initialization file, ghost Kermit processes will be
created, and will compete for the keyboard. They can only be removed
via "kill -9" from another terminal, or by rebooting. Diagnosis --
something strange happening with the SIGINT handler while the process
is reading the directory (it seems to occur during the SET PROMPT
[\v(dir)] ... sequence). Cure: unknown. Workaround: don't interrupt
C-Kermit while it is executing its init file on the Tandy 16/6000.
________________________________________________________________________
3.13. C-KERMIT AND OSF/1 (DIGITAL UNIX) (TRU64 UNIX)
[ [482]Top ] [ [483]Contents ] [ [484]Section Contents ] [ [485]Next ]
[ [486]Previous ]
While putting together and testing C-Kermit 8.0, it was discovered
that binaries built for one version of Tru64 Unix (e.g. 4.0G) might
exhibit very strange behavior if run on a different version of Tru64
Unix (e.g. 5.1A). The typical symptom was that a section of the
initialization file would be skipped, notably locating the dialing
and/or network directory as well as finding and executing the
customization file, ~/.mykermrc. This problem also is reported to
occur on Tru64 Unix 5.0 (Rev 732) even when running a C-Kermit binary
that was built there. However, the Tru64 5.1A binary works correctly
on 5.0. Go figure.
When making Telnet connections to a Digital Unix or Tru64 system, and
your Telnet client forwards your user name, the Telnet server
evidently stuffs the username into login's standard input, and you
see:
login: ivan
Password:
This is clearly going to play havoc with scripts that look for
"login:". Workaround (when Kermit is your Telnet client): SET LOGIN
USER to nothing, to prevent Kermit from sending your user ID.
Before you can use a serial port on a new Digital Unix system, you
must run uucpsetup to enable or configure the port. Evidently the
/dev/tty00 and 01 devices that appear in the configuration are not
usable; uucpsetup turns them into /dev/ttyd00 and 01, which are. Note
that uucpsetup and other uucp-family programs are quite primitive --
they only know about speeds up to 9600 bps and their selection of
modems dates from the early 1980s. None of this affects Kermit, though
-- with C-Kermit, you can use speeds up to 115200 bps (at least in
DU4.0 and later) and modern modems with hardware flow control and all
the rest.
Reportedly, if a modem is set for &S0 (assert DSR at all times), the
system resets or drops DTR every 30 seconds; reportedly DEC says to
set &S1.
Digital Unix 3.2 evidently wants to believe your terminal is one line
longer than you say it is, e.g. when a "more" or "man" command is
given. This is has nothing to do with C-Kermit, but tends to annoy
those who use Kermit or other terminal emulators to access Digital
Unix systems. Workaround: tell Unix to "stty rows 23" (or whatever).
Reportedly, there is some bizarre behavior when trying to use a
version of C-Kermit built on one Digital Unix 4.0 system on another
one, possibly due to differing OS or library revision levels; for
example, the inability to connect to certain TCP/IP hosts. Solution:
rebuild C-Kermit from source code on the system where you will be
using it.
Digital Unix tgetstr() causes a segmentation fault. C-Kermit 7.0 added
#ifdefs to avoid calling this routine in Digital Unix. As a result,
the SCREEN commands always send ANSI escape sequences -- even though
curses knows your actual terminal type.
Reportedy the Tru64 Unix 4.0E 1091 Telnet server does not tolerate
streaming transfers into itself, at least not when the sending Kermit
is on the same local network. Solution: tell one Kermit or the other
(or both) to "set streaming off". This might or might be the case with
earlier and/or later Tru64, Digital Unix, and OSF/1 releases.
________________________________________________________________________
3.14. C-KERMIT AND SGI IRIX
[ [487]Top ] [ [488]Contents ] [ [489]Section Contents ] [ [490]Next ]
[ [491]Previous ]
See also:
* The [492]comp.sys.sgi.misc and [493]comp.sys.sgi.admin newsgroups.
[494]The SGI website
* The SGI FAQ:
+ [495]http://www-viz.tamu.edu/~sgi-faq/
+ [496]ftp://viz.tamu.edu/pub/sgi/faq/
About IRIX version numbers: "uname -a" tells the "two-digit" version
number, such as "5.3" or "6.5". The three-digit form can be seen with
"uname -R". (this information is unavailable at the simple API level).
Supposedly all three-digit versions within the same two-digit version
(e.g. 6.5.2, 6.5.3) are binary compatible; i.e. a binary built on any
one of them should run on all others. The "m" suffix denotes just
patches; the "f" suffix indicates that features were added.
An IRIX binary built on lower MIPS model (Instruction Set
Architecture, ISA) can run on higher models, but not vice versa:
MIPS1 R3000 and below
MIPS2 R4000
MIPS3 R4x00
MIPS4 R5000 and above
Furthermore, there are different Application Binary Inferfaces (ABIs):
COFF 32 bits, IRIX 5.3, 5.2, 5.1, 4.x and below
o32 ELF 32 bits, IRIX 5.3, 6.0 - 6.5
N32 ELF 32 bits, IRIX 6.2 - 6.5
N64 ELF 64 bits, IRIX 6.2 - 6.5
Thus a prebuilt IRIX binary works on a particular machine only if (a)
the machine's IRIX version (to one decimal place) is equal to or
greater than the version under which the binary was built; (b) the
machine's MIPS level is greater or equal to that of the binary; and
(c) the machine supports the ABI of the binary. If all three
conditions are not satisfied, of course, you can build a binary
yourself from source code since, unlike some other Unix vendors, SGI
does supply a C compiler and libraries.
SGI did not supply an API for hardware flow control prior to IRIX 5.2.
C-Kermit 6.1 and higher for IRIX 5.2 and higher supports hardware flow
control in the normal way, via "set flow rts/cts".
For hardware flow control on earlier IRIX and/or C-Kermit versions,
use the ttyf* (modem control AND hardware flow control) devices and
not the ttyd* (direct) or ttym* (modem control but no hardware flow
control) ones, and obtain the proper "hardware handshaking" cable from
SGI, which is incompatible with the ones for the Macintosh and NeXT
even though they look the same ("man serial" for further info) and
tell Kermit to "set flow keep" and "set modem flow rts/cts".
Serial speeds higher than 38400 are available in IRIX 6.2 and later,
on O-class machines (e.g. Origin, Octane) only, and are supported by
C-Kermit 7.0 and later. Commands such as "set speed 115200" may be
given on other models (e.g. Iris, Indy, Indigo) but will fail because
the OS reports an invalid speed for the device.
Experimentation with both IRIX 5.3 and 6.2 shows that when logged in
to IRIX via Telnet, that remote-mode C-Kermit can't send files if the
packet length is greater than 4096; the Telnet server evidently has
this restriction (or bug), since there is no problem sending long
packets on serial or rlogin connections. However, it can receive files
with no problem if the packet length is greater than 4096. As a
workaround, the FAST macro for IRIX includes "set send packet-length
4000". IRIX 6.5.1 does not have this problem, so evidently it was
fixed some time after IRIX 6.2. Tests show file-transfer speeds are
better (not worse) with 8K packets than with 4K packets from IRIX
6.5.1.
Reportedly some Indys have bad serial port hardware. IRIX 5.2, for
example, needs patch 151 to work around this; or upgrade to a later
release. Similarly, IRIX 5.2 has several problems with serial i/o,
flow control, etc. Again, patch or upgrade.
Reportedly on machines with IRIX 4.0, Kermit cannot be suspended by
typing the suspend ("swtch") character if it was started from csh,
even though other programs can be suspended this way, and even though
the Z and SUSPEND commands still work correctly. This is evidently
because IRIX's csh does not deliver the SIGTSTP signal to Kermit. The
reason other programs can be suspended in the same environment is
probably that they do not trap SIGTSTP themselves, so the shell is
doing the suspending rather than the application.
Also see notes about IRIX 3.x in the [497]C-Kermit for Unix
Installation Instructions.
If you have problems making TCP/IP connections in versions of IRIX
built with GCC 2.95.2, see the bugs section of:
[498]http://freeware.sgi.com/Installable/gcc-2.95.2.html.
Reportedly, if you allow gcc to compile C-Kermit on Irix you should be
aware that there might be problems with some of the network code. The
specifics are at
[499]http://freeware.sgi.com/Installable/gcc-2.95.2.html; scroll down
to the "known bugs" section at the end of the document.
________________________________________________________________________
3.15. C-KERMIT AND THE BEBOX
[ [500]Top ] [ [501]Contents ] [ [502]Section Contents ] [ [503]Next ]
[ [504]Previous ]
See also: The [505]comp.sys.be newsgroup.
The BeBox has been discontinued and BeOS repositioned for PC
platforms. The POSIX parts of BeOS are not finished, nor is the
sockets library, therefore a fully functional version of C-Kermit is
not possible. In version 6.0 of C-Kermit, written for BeOS DR7, it was
possible to:
* set line /dev/serial2 (and probably the other serial ports)
* set speed 115200 (and at least some of the lower baud rates)
* connect
* set modem type hayes (and likely others, too)
* dial phone-number
* set send packet-length 2048 (other lengths for both send and
receive)
* set receive packet length 2048
* set file type binary (text mode works, too) (with remote kermit
session in server mode)
* put bedrop.jpg
* get bedrop.jpg
* get bedrop.jpg bedrop.jpg2
* finish, bye
The following do not work:
* kermit does not detect modem hangup
* !/RUN/PUSH [commandline command]
* Running kermit in remote mode
* Using other protocols (x/y/zmodem)
* TCP networking interface (Be's TCP/IP API has a ways to go, still)
C-Kermit does not work on BeOS DR8 because of changes in the
underlying APIs. Unfortunately not enough changes were made to allow
the regular POSIX-based C-Kermit to work either. Note: the lack of a
fork() service requires the select()-based CONNECT module, but there
is no select(). There is a select() in DR8, but it doesn't work.
C-Kermit 7.0 was built for BeOS 4.5 and works in remote mode. It does
not include networking support since the APIs are still not there. It
is not known if dialing out works, but probably not. Be experts are
welcome to lend a hand.
________________________________________________________________________
3.16. C-KERMIT AND DG/UX
[ [506]Top ] [ [507]Contents ] [ [508]Section Contents ] [ [509]Next ]
[ [510]Previous ]
Somebody downloaded the C-Kermit 6.0 binary built under DG/UX 5.40 and
ran it under DG/UX 5.4R3.10 -- it worked OK except that file dates for
incoming files were all written as 1 Jan 1970. Cause and cure unknown.
Workaround: SET ATTRIBUTE DATE OFF. Better: Use a version of C-Kermit
built under and for DG/UX 5.4R3.10.
________________________________________________________________________
3.17. C-KERMIT AND SEQUENT DYNIX
[ [511]Top ] [ [512]Contents ] [ [513]Section Contents ] [ [514]Next ]
[ [515]Previous ]
Reportedly, when coming into a Sequent Unix (DYNIX) system through an
X.25 connection, Kermit doesn't work right because the Sequent's
FIONREAD ioctl returns incorrect data. To work around, use the
1-character-at-a-time version of myread() in ckutio.c (i.e. undefine
MYREAD in ckutio.c and rebuild the program). This is unsatisfying
because two versions of the program would be needed -- one for use
over X.25, and the other for serial and TCP/IP connections.
________________________________________________________________________
3.18. C-KERMIT AND {FREE,OPEN,NET}BSD
[ [516]Top ] [ [517]Contents ] [ [518]Section Contents ] [ [519]Next ]
[ [520]Previous ]
Some NebBSD users have reported difficulty escaping back from CONNECT
mode, usually when running NetBSD on non-PC hardware. Probably a
keyboard issue.
NetBSD users have also reported that C-Kermit doesn't pop back to the
prompt if the modem drops carrier. This needs to be checked out &
fixed if possible.
(All the above seems to work properly in C-Kermit 7.0 and later.)
________________________________________________________________________
3.19. C-KERMIT AND MAC OS X (Rhapsody, Darwin, Jaguar, Panther)
[ [521]Top ] [ [522]Contents ] [ [523]Section Contents ] [ [524]Next ]
[ [525]Previous ]
Mac OS X is Apple's 4.4BSD Unix variety, closely related to FreeBSD,
but different. "uname -a" is singularly uninformative, as in Linux,
giving only the Darwin kernel version number. As far as I can tell,
there is no way to find out the Mac OS X version number, such as 10.3
(in Linux you can find the distribution version in a
distribution-dependent file). Here are some points to be aware of:
* The biggest gotcha for Kermit users is that Mac OS X does not
support serial ports and, as far as I can tell, doesn't support
its built-in modem either, for anything other than making Internet
connections. Macintoshes capable of running Mac OS X, such as the
G5, some without serial ports and without any APIs to support
them, and also without the UUCP family of programs (including cu),
nor any standard for serial-port lockfile directory.
* At least early versions of Mac OS X came without Curses, Termlib,
or Terminfo libraries. Later versions seem to have ncurses. Kermit
uses curses for its file-transfer display. See elsewhere about
curses-vs-ncurses confusion.
* In the HFS+ file system, filenames are case-folded. Thus
"makefile" and "Makefile" are the same file. The UFS file system
is, like normal Unix, case-sensitive.
* Files that are composed of a resource fork and a data fork... I
doubt that C-Kermit does anything useful with them. There is no
code in C-Kermit for traditional two-forked Macintosh files, but
it could be added if there is any demand.
* In case you want to transfer a traditional Macintosh text file (or
data fork of a file that is plain text), you can use these
C-Kermit commands:
set file eol cr
set file character-set apple-quickdraw
send /text filename
* File or pathnames that include spaces must be enclosed in either
doublequotes or curly braces in C-Kermit commands.
* Mac OS X has its own package format for applications, called
"fink". Various fink packages for C-Kermit are floating around
that are not standard releases. For example, there's a C-Kermit
8.0.201 package in which C-Kermit was modifed (at least) to use a
UUCP lockfile directory that does not exist on vanilla Mac OS X
systems.
Mac OS X and Serial Ports
Apple is in the forefront of companies that believe serial ports have
no use in the modern world and so has simply eliminated all traces of
them from its machines and OS. But of course serial ports are still
needed to connect not only to external modems, but also to the control
ports of hubs, routers, terminal servers, PBXs, and similar devices,
not to mention barcode readers, POS systems and components, automated
factory-floor equipment, and scientific, medical, and lab equipment
(to name a few). Among workers in these areas, there is a need to add
serial ports back onto this platform, which is being filled by
third-party products such as the [526]Keyspan USB Serial Adapter. To
use the Keyspan device, you must install the accompanying device
drivers, which wind up giving you serial ports with names like
/dev/cu.USA19H3b1P1.1.
To configure your Mac OS X system to allow C-Kermit to use these (or
any other) serial devices:
1. su
chgrp xxxx /var/spool/lock
chmod g+w /var/spool/lock
chgrp xxxx /dev/cu.*
(where xxxx is the name of the group for users to whom serial-port
access is to be granted). Use "admin" or other existing group, or
create a new group if desired. NB:
In the absence of official guidance from Apple or anyone else, we
choose /var/spool/lock as the lockfile directory because this
directory (a) already exists on vanilla Mac OS X installations, and
(b) it is the directory used for serial-port lockfiles on many
other platforms.
2. Put all users who need access to the serial port in the same
group.
3. Make sure the serial device files that are to be used by C-Kermit
have group read-write permission and (if you care) lack world
read-write permission, e.g.:
chmod g+rw,o-rw /dev/cu.*
If you do the above, then there's no need to become root to use
Kermit, or to make Kermit suid or sgid. Just do this:
chmod 775 wermit
mv wermit /usr/local/bin/kermit
(or whatever spot is more appropriate). For greater detail about
installation (man page, etc), [527]CLICK HERE.
Back when Macs had serial ports, they were not RS-232 (the standard
for connecting computers with nearby modems) but rather RS-422 or -423
(a standard for connecting serial devices over longer distances).
Macintosh serial ports do not support modems well because they do not
have enough wires (or more properly in the case RS-422/423, wire
pairs) to convey a useful subset of modem signals. The Keyspan USB
adapter gives you two Mini-Din8 RS-422 ports, that are no better (or
worse) for communicating with modems or serial devices than a real Mac
Din-8 port was. In essense, you get Data In, Data Out, and two modem
signals. It looks to me as if the signals chosen by Keyspan are RTS
and CTS. This gives you hardware flow control, but at the expense of
Carrier Detect. Thus to use C-Kermit with a Keyspan USB serial port,
you must tell C-Kermit to:
set modem type none ; (don't expect a modem)
set carrier-watch off ; (ignore carrier signal)
set port /dev/cu.USA19H3b1P1.1 ; (open the port)
set flow rts/cts ; (this is the default)
set speed 57600 ; (or whatever)
connect ; (or whatever)
Use Ctrl-\C in the normal manner to escape back to the C-Kermit>
prompt. Kermit can't pop back to its prompt automatically when Carrier
drops because there is no Carrier signal.
Instructions for the built-in modem remain to be written.
Links:
* [528]Unix tips for Mac OS X (Jerry Stratton)
________________________________________________________________________
3.20. C-KERMIT AND COHERENT
[ [529]Top ] [ [530]Contents ] [ [531]Section Contents ] [
[532]Previous ]
Also see:
[533]http://www.uni-giessen.de/faq/archiv/coherent-faq.general/msg00
000.html
Mark Williams COHERENT was perhaps the first commercial Unix-based
operating system for PCs, first appearing about 1983 or -84 for the
PC/XT (?), and popular until about 1993, when Linux took over.
C-Kermit, as of version 8.0, is still current for COHERENT 386 4.2
(i.e. only for i386 and above). Curses is included, but lots of other
features are omitted due to lack of the appropriate OS features, APIs,
libraries, hardware, or just space: e.g. TCP/IP, floating-point
arithmetic, learned scripts. Earlier versions of COHERENT ran on 8086
and 80286, but these are to small to build or run C-Kermit, but
G-Kermit should be OK (as might be ancient versions of C-Kermit).
You can actually build a version with floating point support -- just
take -DNOFLOAT out of CFLAGS and add -lm to LIBS; NOFLOAT is the
default because COHERENT tends to run on old PCs that don't have
floating-point hardware. You can also add "-f" to CFLAGS to have it
link in the floating-point emulation library. Also I'm not sure why
-DNOLEARN is included, since it depends on select(), which COHERENT
has.
________________________________________________________________________
4. GENERAL UNIX-SPECIFIC HINTS, LIMITATIONS, AND BUGS
[ [534]Top ] [ [535]Contents ] [ [536]Next ] [ [537]Previous ]
4.1. Modem Signals
There seems to be an escalating demand for the ability to control
"dumb serial devices" (such as "smartcard readers", barcode readers,
etc) by explicitly manipulating modem signals, particularly RTS. This
might have been easy to do in DOS, where there is no operating system
standing between the application and the serial device, but it is
problematic in Unix, where modem signals are controlled by the serial
device driver. If the driver does not provide an API for doing this,
then the application can't do it. If it does provide an API, expect it
to be totally different on each Unix platform, since there is no
standard for this.
4.2. NFS Troubles
Beginning with C-Kermit 6.0, the default C-Kermit prompt includes your
current (working) directory; for example:
[/usr/olga] C-Kermit>
(In C-Kermit 7.0 the square braces were replaced by round parentheses
to avoid conflicts with ISO 646 national character sets.)
If that directory is on an NFS-mounted disk, and NFS stops working or
the disk becomes unavailable, C-Kermit will hang waiting for NFS
and/or the disk to come back. Whether you can interrupt C-Kermit when
it is hung this way depends on the specific OS. Kermit has called the
operating systems's getcwd() function, and is waiting for it to
return. Some versions of Unix (e.g. HP-UX 9.x) allow this function to
be interrupted with SIGINT (Ctrl-C), others (such as HP-UX 8.x) do
not. To avoid this effect, you can always use SET PROMPT to change
your prompt to something that does not involve calling getcwd(), but
if NFS is not responding, C-Kermit will still hang any time you give a
command that refers to an NFS-mounted directory. Also note that in
some cases, the uninterruptibility of NFS-dependent system or library
calls is considered a bug, and sometimes there are patches. For HP-UX,
for example:
replaced by:
HP-UX 10.20 libc PHCO_8764 PHCO_14891/PHCO_16723
HP-UX 10.10 libc PHCO_8763 PHCO_14254/PHCO_16722
HP-UX 9.x libc PHCO_7747 S700 PHCO_13095
HP-UX 9.x libc PHCO_6779 S800 PHCO_11162
4.3. C-Kermit as Login Shell
You might have reason to make C-Kermit the login shell for a specific
user, by entering the pathname of Kermit (possibly with command-line
switches, such as -x to put it in server mode) into the shell field of
the /etc/passwd file. This works pretty well. In some cases, for
"ultimate security", you might want to use a version built with
-DNOPUSH (see the [538]Configurations Options document for this, but
even if you don't, then PUSHing or shelling out from C-Kermit just
brings up a new copy of C-Kermit (but warning: this does not prevent
the user from explicitly running a shell; e.g. "run /bin/sh"; use
NOPUSH to prevent this).
4.4. C-Kermit versus screen and splitvt
C-Kermit file transfers will probably not work if attemped through the
"splitvt" or GNU "screen" programs because the screen optimization (or
at least, line wrapping, control-character absorption) done by this
package interferes with Kermit's packets.
The same can apply to any other environment in which the user's
session is captured, monitored, recorded, or manipulated. Examples
include the 'script' program (for making a typescript of a session),
the Computronics PEEK package and pksh (at least versions of it prior
to 1.9K), and so on.
You might try the following -- what we call "doomsday Kermit" --
settings to push packets through even the densest and most obstructive
connections, such as "screen" and "splitvt" (and certain kinds of 3270
protocol emulators): Give these commands to BOTH Kermit programs:
SET FLOW NONE
SET CONTROL PREFIX ALL
SET RECEIVE PACKET-LENGTH 70
SET RECEIVE START 62
SET SEND START 62
SET SEND PAUSE 100
SET BLOCK B
If it works, it will be slow.
4.5. C-Kermit versus DOS Emulators
On Unix workstations equipped with DOS emulators like SoftPC, watch
out for what these emulators do to the serial port drivers. After
using a DOS emulator, particularly if you use it to run DOS
communications software, you might have to reconfigure the serial
ports for use by Unix.
4.6. C-Kermit versus Job Control
Interruption by Ctrl-Z makes Unix C-Kermit try to suspend itself with
kill(0,SIGTSTP), but only on platforms that support job control, as
determined by whether the symbol SIGTSTP is defined (or on POSIX or
SVR4 systems, if syconf(_SC_JOB_CONTROL) or _POSIX_JOB_CONTROL in
addition to SIGTSTP). However, if Kermit is running under a login
shell (such as the original Bourne shell) that does not support job
control, the user's session hangs and must be logged out from another
terminal, or hung up on. There is no way Kermit can defend itself
against this. If you use a non-job control shell on a computer that
supports job control, give a command like "stty susp undef" to fix it
so the suspend signal is not attached to any particular key, or give
the command SET SUSPEND OFF to C-Kermit, or build C-Kermit with
-DNOJC.
4.7. Dates and Times
Unix time conversion functions typically apply locale rules to return
local time in terms of any seasonal time zone change in effect for the
given date. The diffdate function assumes that the same timezone rules
are in effect for both dates, but a date with timezone information
will be converted to the local time zone in effect at the given time,
e.g., a GMT specification will produce either a Standard Time or
Daylight Savings Time, depending on which applies at the given time.
An example using the 2001 seasonal change from EDT (-0400) to EST
(-0500):
C-Kermit> DATE 20011028 05:01:02 GMT ; EDT
20011028 01:01:02
C-Kermit> DATE 20011028 06:01:02 GMT ; EST
20011028 01:01:02
C-Kermit>
but the implicit change in timezone offset is not recognized:
C-Kermit> echo \fdiffdate(20011028 05:01:02 GMT, 20011028 06:01:02 GMT)
+0:00
C-Kermit>
Date/time arithmetic, offsets, delta times, and timezone support are
new to C-Kermit 8.0, and might be expected to evolve and improve in
subsequent releases.
On some platforms, files downloaded with HTTP receive the current
timestamp, rather than the HTTP "Last Modified" time (this can be
fixed by including utime.h, e.g. in SunOS and Tru64...).
4.8. Pseudoterminals
The SSH and PTY commands work by assigning a pseudoterminal and
reading and writing from it. Performance varies according to the
specific platform ranging from very fast to very flow.
SSH and PTY commands can fail if (a) all pseudoterminals are in use;
or (b) you do not have read/write access to the pseudoterminal that
was assigned. An example of (b) was reported with the Zipslack
Slackware Linux distribution, in which the pseudoterminals were
created with crw-r--r-- permission, instead of crw-rw-rw-.
4.9. Miscellaneous
* Reportedly, the Unix C-Kermit server, under some conditions, on
certain particular systems, fails to log out its login session
upon receipt of a BYE command. Before relying on the BYE command
working, test it a few times to make sure it works on your system:
there might be system configuration or security mechanisms to
prevent an inferior process (like Kermit) from killing a superior
one (like the login shell).
* On AT&T 7300 (3B1) machines, you might have to "stty nl1" before
starting C-Kermit. Do this if characters are lost during
communications operations.
* Under the bash shell (versions prior to 1.07 from CWRU), "pushing"
to an inferior shell and then exiting back to Kermit leaves Kermit
in the background such that it must be explicitly fg'd. This is
reportedly fixed in version 1.07 of bash (and definitely in modern
bash versions).
________________________________________________________________________
5. INITIALIZATION AND COMMAND FILES
[ [539]Top ] [ [540]Contents ] [ [541]Next ] [ [542]Previous ]
C-Kermit's initialization file for Unix is .kermrc (lowercase, starts
with period) in your home directory, unless Kermit was built with the
system-wide initialization-file option (see the [543]C-Kermit for Unix
Installation Instructions).
C-Kermit identifies your home directory based on the environment
variable, HOME. Most Unix systems set this variable automatically when
you log in. If C-Kermit can't find your initialization file, check
your HOME variable:
echo $HOME (at the Unix prompt)
or:
echo \$(HOME) (at the C-Kermit prompt)
If HOME is not defined, or is defined incorrectly, add the appropriate
definition to your Unix .profile or .login file, depending on your
shell:
setenv HOME full-pathname-of-your-home-directory (C-Shell, .login file)
or:
HOME=full-pathname-of-your-home-directory (sh, ksh, .profile file)
export HOME
NOTE: Various other operations depend on the correct definition of
HOME. These include the "tilde-expansion" feature, which allows you to
refer to your home directory as "~" in filenames used in C-Kermit
commands, e.g.:
send ~/.kermrc
as well as the \v(home) variable.
Prior to version 5A(190), C-Kermit would look for its initialization
file in the current directory if it was not found in the home
directory. This feature was removed from 5A(190) because it was a
security risk. Some people, however, liked this behavior and had
.kermrc files in all their directories that would set up things
appropriately for the files therein. If you want this behavior, you
can accomplish it in various ways, for example:
* Create a shell alias, for example:
alias kd="kermit -Y ./.kermrc"
* Create a .kermrc file in your home directory, whose contents are:
take ./.kermrc
Suppose you need to pass a password from the Unix command line to a
C-Kermit script program, in such a way that it does not show up in
"ps" or "w" listings. Here is a method (not guaranteed to be 100%
secure, but definitely more secure than the more obvious methods):
echo mypassword | kermit myscript
The "myscript" file contains all the commands that need to be executed
during the Kermit session, up to and including EXIT, and also includes
an ASK or ASKQ command to read the password from standard input, which
has been piped in from the Unix 'echo' command, but it must not
include a CONNECT command. Only "kermit myscript" shows up in the ps
listing.
________________________________________________________________________
6. COMMUNICATION SPEED SELECTION
[ [544]Top ] [ [545]Contents ] [ [546]Next ] [ [547]Previous ]
Version-7 based Unix implementations, including 4.3 BSD and earlier
and Unix systems based upon BSD, use a 4-bit field to record a serial
device's terminal speed. This leaves room for 16 speeds, of which the
first 14 are normally:
0, 50, 75, 110, 134.5, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
and 9600
The remaining two are usually called EXTA and EXTB, and are defined by
the particular Unix implementation. C-Kermit determines which speeds
are available on your system based on whether symbols for them are
defined in your terminal device header files. EXTA is generally
assumed to be 19200 and EXTB 38400, but these assumptions might be
wrong, or they might not apply to a particular device that does not
support these speeds. Presumably, if you try to set a speed that is
not legal on a particular device, the driver will return an error, but
this can not be guaranteed.
On these systems, it is usually not possible to select a speed of
14400 bps for use with V.32bis modems. In that case, use 19200 or
38400 bps, configure your modem to lock its interface speed and to use
RTS/CTS flow control, and tell C-Kermit to SET FLOW RTS/CTS and SET
DIAL SPEED-MATCHING OFF.
The situation is similar, but different, in System V. SVID Third
Edition lists the same speeds, 0 through 38400.
Some versions of Unix, and/or terminal device drivers that come with
certain third-party add-in high-speed serial communication interfaces,
use the low "baud rates" to stand for higher ones. For example, SET
SPEED 50 gets you 57600 bps; SET SPEED 75 gets you 76800; SET SPEED
110 gets 115200.
SCO ODT 3.0 is an example where a "baud-rate-table patch" can be
applied that can rotate the tty driver baud rate table such that
600=57600 and 1800=115k baud. Similarly for Digiboard
multiport/portservers, which have a "fastbaud" setting that does this.
Linux has a "setserial" command that can do it, etc.
More modern Unixes support POSIX-based speed setting, in which the
selection of speeds is not limited by a 4-bit field. C-Kermit 6.1
incorporates a new mechanism for finding out (at compile time) which
serial speeds are supported by the operating system that does not
involve editing of source code by hand; on systems like Solaris 5.1,
IRIX 6.2, and SCO OSR5.0.4, "set speed ?" will list speeds up to
460800 or 921600. In C-Kermit 7.0 and later:
1. If a symbol for a particular speed (say B230400 for 230400 bps)
appears in whatever header file defines acceptable serial speeds
(e.g. <termbits.h> or <sys/termios.h> or <sys/ttydev.h>, etc), the
corresponding speed will appear in C-Kermit's "set speed ?" list.
2. The fact that a given speed is listed in the header files and
appears in C-Kermit's list does not mean the driver will accept
it. For example, a computer might have some standard serial ports
plus some add-on ones with different drivers that accept a
different repertoire of speeds.
3. The fact that a given speed is accepted by the driver does not
guarantee the underlying hardware can accept it.
When Kermit is given a "set speed" command for a particular device,
the underlying system service is called to set the speed; its return
code is checked and the SET SPEED command fails if the return code
indicates failure. Regardless of the system service return status, the
device's speed is then read back and if it does not match the speed
that was requested, an error message is printed and the command fails.
Even when the command succeeds, this does not guarantee successful
operation at a particular speed, especially a high one. That depends
on electricity, information theory, etc. How long is the cable, what
is its capacitance, how well is it shielded, etc, not to mention that
every connection has two ends and its success depends on both of them.
(With the obvious caveats about internal modems, is the cable really
connected, interrupt conflicts, etc etc etc).
Note, in particular, that there is a certain threshold above which
modems can not "autobaud" -- i.e. detect the serial interface speed
when you type AT (or whatever else the modem's recognition sequence
might be). Such modems need to be engaged at a lower speed (say 2400
or 9600 or even 115200 -- any speed below their autobaud threshold)
and then must be given a modem-specific command (which can be found in
the modem manual) to change their interface speed to the desired
higher speed, and then the software must also be told to change to the
new, higher speed.
For additional information, read [548]Section 9.5 of the Installation
Instructions, plus any platform-specific notes in [549]Section 3
above.
________________________________________________________________________
7. COMMUNICATIONS AND DIALING
[ [550]Top ] [ [551]Contents ] [ [552]Next ] [ [553]Previous ]
7.1. Serial Ports and Modems
If you SET LINE to a serial port modem-control device that has nothing
plugged in to it, or has a modem connected that is powered off, and
you have not given a prior SET MODEM TYPE or SET CARRIER-WATCH OFF
command, the SET LINE command is likely to hang. In most cases, you
can Ctrl-C out. If not, you'll have to kill C-Kermit from another
terminal.
Similarly, if you give a SET MODEM TYPE HAYES (or USR, or any other
modem type besides DIRECT, NONE, or UNKNOWN) and then SET LINE to an
empty port, the subsequent close (implicit or explicit) is liable to
hang or even crash (through no fault of Kermit's -- the hanging or
crashing is inside a system call such as cfsetospeed() or close()).
The SET CARRIER-WATCH command works as advertised only if the
underlying operating system and device drivers support this feature;
in particular only if a read() operation returns immediately with an
error code if the carrier signal goes away or, failing that, if
C-Kermit can obtain the modem signals from the device driver (you can
tell by giving a "set line" command to a serial device, and then a
"show communications" command -- if modem signals are not listed,
C-Kermit won't be able to detect carrier loss, the WAIT command will
not work, etc). Of course, the device itself (e.g. modem) must be
configured appropriately and the cables convey the carrier and other
needed signals, etc.
If you dial out from Unix system, but then notice a lot of weird
character strings being stuck into your session at random times
(especially if they look like +++ATQ0H0 or login banners or prompts),
that means that getty is also trying to control the same device.
You'll need to dial out on a device that is not waiting for a login,
or else disable getty on the device.
As of version 7.0, C-Kermit makes explicit checks for the Carrier
Detect signal, and so catches hung-up connections much better than 6.0
and earlier. However, it still can not be guaranteed to catch every
ever CD on-to-off transition. For example, when the HP-UX version of
C-Kermit is in CONNECT mode on a dialed connection and CARRIER-WATCH
ON or AUTO, and you turn off the modem, HP-UX is stuck in a read()
that never returns. (C-Kermit does not pop back to its prompt
automatically, but you can still escape back.)
If, on the other hand, you log out from the remote system, and it
hangs up, and CD drops on the local modem, C-Kermit detects this and
pops back to the prompt as it should. (Evidently there can be a
difference between CD and DSR turning off at the same time, versus CD
turning off while DSR stays on; experimentation with &S0/&S1/&S2 on
your modem might produce the desired results).
When Unix C-Kermit exits, it closes (and must close) the
communications device. If you were dialed out, this will most likely
hang up the connection. If you want to get out of Kermit and still use
Kermit's communication device, you have several choices:
1. Shell out from Kermit or suspend Kermit, and refer to the device
literally (as in "term -blah -blah < /dev/cua > /dev/cua").
2. Shell out from Kermit and use the device's file descriptor which
Kermit makes available to you in the \v(ttyfd) variable.
3. Use C-Kermit's REDIRECT command.
4. Use C-Kermit new EXEC /REDIRECT command.
If you are having trouble dialing:
1. Make sure the dialout line is configured correctly. More about
this below.
2. Make sure all necessary patches are installed for your operating
system.
3. If you can't dial on a "bidirectional" line, then configure it for
outbound-only (remove the getty) and try again. (The mechanisms --
if any -- for grabbing bidirectional lines for dialout vary wildly
among Unix implementations and releases, and C-Kermit -- which
runs on well over 300 different Unix variations -- makes no effort
to keep up with them; the recommended method for coping with this
situation is to wrap C-Kermit in a shell script that takes the
appropriate actions.)
4. Make sure C-Kermit's SET DIAL and SET MODEM parameters agree with
the modem you are actually using -- pay particular attention to
SET DIAL SPEED-MATCHING.
5. If MODEM HANGUP-METHOD is set to RS232-SIGNAL, change it to
MODEM-COMMAND. Or vice-versa.
6. Try SET DIAL HANGUP OFF before the DIAL command. Also, SET DIAL
DISPLAY ON to watch what's happening. See [554]Section 8 of the
[555]Installation Instructions.
7. Read pages 50-67 of [556]Using C-Kermit.
8. As a last resort, don't use the DIAL command at all; SET CARRIER
OFF and CONNECT to the modem and dial interactively, or write a
script program to dial the modem.
Make sure your dialout line is correctly configured for dialing out
(as opposed to login). The method for doing this is different for each
kind of Unix system. Consult your system documentation for configuring
lines for dialing out (for example, Sun SparcStation IPC users should
read the section "Setting up Modem Software" in the Desktop SPARC Sun
System & Network Manager's Guide; HP-9000 workstation users should
consult the manual Configuring HP-UX for Peripherals, etc).
Symptom: DIAL works, but a subsequent CONNECT command does not.
Diagnosis: the modem is not asserting Carrier Detect (CD) after the
connection is made, or the cable does not convey the CD signal. Cure:
Reconfigure the modem, replace the cable. Workaround: SET CARRIER OFF
(at least in System-V based Unix versions).
For Berkeley-Unix-based systems (4.3BSD and earlier), Kermit includes
code to use LPASS8 mode when parity is none, which is supposed to
allow 8-bit data and Xon/Xoff flow control at the same time. However,
as of edit 174, this code is entirely disabled because it is
unreliable: even though the host operating system might (or might not)
support LPASS8 mode correctly, the host access protocols (terminal
servers, telnet, rlogin, etc) generally have no way of finding out
about it and therefore render it ineffective, causing file transfer
failures. So as of edit 174, Kermit once again uses rawmode for 8-bit
data, and so there is no Xon/Xoff flow control during file transfer or
terminal emulation in the Berkeley-based versions (4.3 and earlier,
not 4.4).
Also on Berkeley-based systems (4.3 and earlier), there is apparently
no way to configure a dialout line for proper carrier handling, i.e.
ignore carrier during dialing, require carrier thereafter, get a fatal
error on any attempt to read from the device after carrier drops (this
is handled nicely in System V by manipulation of the CLOCAL flag). The
symptom is that carrier loss does not make C-Kermit pop back to the
prompt automatically. This is evident on the NeXT, for example, but
not on SunOS, which supports the CLOCAL flag. This is not a Kermit
problem, but a limitation of the underlying operating system. For
example, the cu program on the NeXT doesn't notice carrier loss
either, whereas cu on the Sun does.
On certain AT&T Unix systems equipped with AT&T modems, DIAL and
HANGUP don't work right. Workarounds: (1) SET DIAL HANGUP OFF before
attempting to dial; (2) If HANGUP doesn't work, SET LINE, and then SET
LINE <device> to totally close and reopen the device. If all else
fails, SET CARRIER OFF.
C-Kermit does not contain any particular support for AT&T DataKit
devices. You can use Kermit software to dial in to a DataKit line, but
C-Kermit does not contain the specialized code required to dial out
from a DataKit line. If the Unix system is connected to DataKit via
serial ports, dialout should work normally (e.g. set line /dev/ttym1,
set speed 19200, connect, and then see the DESTINATION: prompt, from
which you can connect to another computer on the DataKit network or to
an outgoing modem pool, etc). But if the Unix system is connected to
the DataKit network through the special DataKit interface board, then
SET LINE to a DataKit pseudodevice (such as /dev/dk031t) will not work
(you must use the DataKit "dk" or "dkcu" program instead). In C-Kermit
7.0 and later, you can make Kermit connections "though" dk or dkcu
using "set line /pty".
In some BSD-based Unix C-Kermit versions, SET LINE to a port that has
nothing plugged in to it with SET CARRIER ON will hang the program (as
it should), but it can't be interrupted with Ctrl-C. The interrupt
trap is correctly armed, but apparently the Unix open() call cannot be
interrupted in this case. When SET CARRIER is OFF or AUTO, the SET
LINE will eventually return, but then the program hangs
(uninterruptibly) when the EXIT or QUIT command (or, presumably,
another SET LINE command) is given. The latter is probably because of
the attempt to hang up the modem. (In edit 169, a timeout alarm was
placed around this operation.)
With SET DIAL HANGUP OFF in effect, the DIAL command might work only
once, but not again on the same device. In that case, give a CLOSE
command to close the device, and then another SET LINE command to
re-open the same device. Or rebuild your version of Kermit with the
-DCLSOPN compile-time switch.
The DIAL command says "To cancel: Type your interrupt character
(normally Ctrl-C)." This is just one example of where program messages
and documentation assume your interrupt character is Ctrl-C. But it
might be something else. In most (but not necessarily all) cases, the
character referred to is the one that generates the SIGINT signal. If
Ctrl-C doesn't act as an interrupt character for you, type the Unix
command "stty -a" or "stty all" or "stty everything" to see what your
interrupt character is. (Kermit could be made to find out what the
interrupt character is, but this would require a lot of
platform-dependent coding and #ifdefs, and a new routine and interface
between the platform-dependent and platform-independent parts of the
program.)
In general, the hangup operation on a serial communication device is
prone to failure. C-Kermit tries to support many, many different kinds
of computers, and there seems to be no portable method for hanging up
a modem connection (i.e. turning off the RS-232 DTR signal and then
turning it back on again). If HANGUP, DIAL, and/or Ctrl-\H do not work
for you, and you are a programmer, look at the tthang() function in
ckutio.c and see if you can add code to make it work correctly for
your system, and send the code to the address above. (NOTE: This
problem has been largely sidestepped as of edit 188, in which Kermit
first attempts to hang up the modem by "escaping back" via +++ and
then giving the modem's hangup command, e.g. ATH0, when DIAL
MODEM-HANGUP is ON, which is the default setting.)
Even when Kermit's modem-control software is configured correctly for
your computer, it can only work right if your modem is also configured
to assert the CD signal when it is connected to the remote modem and
to hang up the connection when your computer drops the DTR signal. So
before deciding Kermit doesn't work with your modem, check your modem
configuration AND the cable (if any) connecting your modem to the
computer -- it should be a straight-through modem cable conducting the
signals FG, SG, TD, RD, RTS, CTS, DSR, DTR, CD, and RI.
Many Unix systems keep aliases for dialout devices; for example,
/dev/acu might be an alias for /dev/tty00. But most of these Unix