SGI O2
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Silicon Graphics, Inc. | |
Release date | October 1996 |
---|---|
Operating system | IRIX |
CPU | R5000, RM7000, R10000, or R12000 |
Memory | 32 MB (up to 1 GB) |
Predecessor | SGI Indy |
The O2 is an entry-level Unix workstation introduced in 1996 by Silicon Graphics, Inc. (SGI) to replace their earlier Indy series. Like the Indy, the O2 uses a single MIPS microprocessor and was intended to be used mainly for multimedia. Its larger counterpart is the SGI Octane. The O2 was SGI's last attempt at a low-end workstation.
Hardware
System architecture
Originally known as the "Moosehead" project, the O2
CPU
The O2 came in two distinct CPU flavours: the low-end MIPS 180 to 350 MHz R5000- or RM7000-based units and the higher-end 150 to 400 MHz R10000- or R12000-based units. The 200 MHz R5000 CPUs with 1 MB L2-cache are generally noticeably faster than the 180 MHz R5000s with 512 KB cache. There is a hobbyist project that has successfully retrofitted a 600 MHz RM7xxx MIPS processor into the O2.
Memory
There are eight DIMM slots on the motherboard and memory, and all O2s are expandable to 1 GB using proprietary 239-pin
I/O
I/O functionality is provided by the IO Engine ASIC. The ASIC provides a 64-bit PCI bus, an ISA bus, two PS/2 ports for keyboard and mouse, and a 10/100 Base-T Ethernet port. The PCI bus has one 64-bit slot, but the ISA bus is present solely for attaching a Super I/O chip to provide serial and parallel ports.
Disks
The O2 carries an UltraWide SCSI drive subsystem (Adaptec 7880). Older O2's generally have 4x speed Toshiba CD-ROMs, but any Toshiba SCSI CD-ROM can be used (as well as from other manufacturers, the bezel replacement however is designed to fit Toshiba design and also IRIX cannot utilize
Graphics
The O2 used the CRM chipset specifically developed by SGI for the O2. It was developed to be a low-cost implementation of the
Operating systems
Several operating systems support the O2:
- IRIX 6.3 or 6.5.x (native platform).
- Linux port is working, but some drivers are missing. Debian, Gentoo and T2 Linux have releases that work on the O2. See the IP32 port page on linux-mips.org.
- OpenBSD ran on the O2 starting from OpenBSD 3.7 until the discontinuation of the "sgi" port in OpenBSD 6.9.[2]
- port page.
Performance
The SGI O2 has an Imaging and Compression Engine (ICE)
The Unified Memory Architecture means that the O2 uses main memory for graphics textures, making texturing polygons and other graphics elements trivial. Instead of transferring textures over a bus to the graphics subsystem, the O2 passes a pointer to the texture in main memory which is then accessed by the graphics hardware. This makes using large textures easy, and even makes using streaming video as a texture possible.
Since the CPU performs many of geometry calculations, using a faster CPU will increase the speed of a geometry-limited application. The O2's graphics is known to have slower rasterization speed than the Indigo2's Maximum IMPACT graphics boards, though the Maximum IMPACT graphics is limited to 4 MB of texture memory, which can result in thrashing, whereas the O2 is limited only by available memory.
While CPU frequencies of 180 to 400 MHz seem low today, when the O2 was released in 1996, these speeds were on par with or above the current offerings for the x86 family of computers (cf. Intel's
Uses
O2s were often used in the following fields:
- Imaging (especially medical)
- On-air TV graphics; the most widespread example of an O2 running TV graphics is the Weather Star XL computer for The Weather Channel
- Desktop workstation
- 3D modelling
- Analogue video post-production
- Defense industries
SGI timeline
References
- ^ "SGI O2 R5000". Majix Hardware web site. Retrieved August 3, 2013. (includes photos)
- ^ "OpenBSD sgi".
- ^ NetBSD ported to SGI O2
- ^ a b c Kilgard, Mark J. (1997). "Realizing OpenGL: Two implementations of one architecture". 1997 SIGGRAPH/Eurographics Workshop, pp. 45–55.