SGI Visual Workstation

SGI Visual Workstation is a series of workstation computers that were designed and manufactured by SGI. Unlike its other product lines, which used the 64-bit MIPS RISC architecture, the line used Intel Pentium II and III processors and shipped with Windows NT 4.0 or Windows 2000 as its operating system in lieu of IRIX. However, the Visual Workstation 320 and 540 models deviated from the architecture of IBM-compatible PCs by using SGI's ARCS firmware instead of a traditional BIOS, internal components adapted from its MIPS-based products, and other proprietary components that made them incompatible with internal hardware designed for standard PCs and hence unable to run Windows 9x.

By contrast, the remaining models in the line were standard PCs, using VIA Technologies chipsets, Nvidia video cards, and standard components.

There were really two series of the Visual Workstations. All were based on Intel processors; the first series (320 and 540) used SGI's ARCloader PROM and Cobalt video chipset, the remainder were essentially standard PC's.

The 320 and 540 used a Unified Memory Architecture (UMA) memory system. This shared the video and system memory and ran them at the same speed, and allowed for up to 80 percent of the system ram to be applied to video memory. The allocation was static, however, and was adjusted via a profile. The 320 and 540 also used the onboard Cobalt video adapter, which was SGI's proprietary graphics chipset. The firmware the systems used was a PROM that enabled booting into a graphical subsystem before the OS was loaded. In this regard they resembled the Irix/MIPS line of SGI computers such as the SGI O2.

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