| 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. |