|The SGI Visual Workstations (models 320 and 540) are based around
|the Cobalt, Lithium, and Arsenic ASICs. The Cobalt ASIC is the
|main system ASIC which interfaces the 1-4 IA32 cpus, the memory
|system, and the I/O system in the Lithium ASIC. The Cobalt ASIC
|also contains the 3D gfx rendering engine which renders to main
|system memory -- part of which is used as the frame buffer which
|is DMA'ed to a video connector using the Arsenic ASIC. A PIIX4
|chip and NS87307 are used to provide legacy device support (IDE,
|serial, floppy, and parallel).
|The Visual Workstation chipset largely conforms to the PC architecture
|with some notable exceptions such as interrupt handling.