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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. By contrast, the remaining models in the line were standard PCs, using VIA Technologies chipsets, Nvidia video cards, and standard components. ==Computer architecture== 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 on board 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. The 320 and 540 also stood out for having Firewire (IEEE 1394) ports, on board composite/s-video capture, and USB keyboards and mice. They differed from each other in the 320 was dual Pentium II/III capable with 1GB maximum system RAM, while the 540 was quad Pentium III Xeon capable with 2GB maximum system RAM. Both computers used a proprietary DIMM module that was essentially the same as ECC SDRAM PC-100, but in a package one half normal size. The maximum memory per module was 96MB, and the SGI 320 had twelve memory slots. It is important to note that the Firewire ports that were built into the 320 never functioned. SGI distributed Orange Micro Firewire cards about a year after production started in lieu of fixing the Firewire ports. Both the 320 and 540 were further limited by having PCI slots (albeit two 66 MHz and one 33 MHz slot) that operated at 3.3V, out of step with the 5v slots used by most manufacturers. This limited the number of accessories that could be added. The other Visual Workstations were built to compete with the new Intel processor based workstations that were considerably cheaper than SGI's line of MIPS workstations. They were little more than standard PCs, and used many parts that were also available in the aftermarket. They were criticized for using very cheap components, such as motherboards based on the VIA Apollo chipset for the SGI 230. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「SGI Visual Workstation」の詳細全文を読む スポンサード リンク
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