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The O2 was an entry-level
Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
workstation A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workstat ...
introduced in 1996 by
Silicon Graphics, Inc. Silicon Graphics, Inc. (stylized as SiliconGraphics before 1999, later rebranded SGI, historically known as Silicon Graphics Computer Systems or SGCS) was an American high-performance computing manufacturer, producing computer hardware and soft ...
(SGI) to replace their earlier
Indy Indy may refer to: Computing and technology *Indy (software), used for Internet access to music *Internet Direct, or "Indy", a software library *SGI Indy, a computer workstation Periodicals *''The Indy'', shorthand for newspapers that include " ...
series. Like the Indy, the O2 used a single MIPS
microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
and was intended to be used mainly for
multimedia Multimedia is a form of communication that uses a combination of different content forms such as text, audio, images, animations, or video into a single interactive presentation, in contrast to tradition ...
. Its larger counterpart was the
SGI Octane SGI may refer to: Companies *Saskatchewan Government Insurance *Scientific Games International, a gambling company *Silicon Graphics, Inc., a former manufacturer of high-performance computing products *Silicon Graphics International, formerly Rac ...
. The O2 was SGI's last attempt at a low-end workstation.


Hardware


System architecture

Originally known as the "Moosehead" project, the O2
architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing building ...
featured a proprietary high-bandwidth
Unified Memory Architecture Unified may refer to: * The Unified, a wine symposium held in Sacramento, California, USA * ''Unified'', the official student newspaper of Canterbury Christ Church University * UNFD, an Australian record label * ''Unified'' (Sweet & Lynch album) ...
(UMA) to connect system components. A
PCI PCI may refer to: Business and economics * Payment card industry, businesses associated with debit, credit, and other payment cards ** Payment Card Industry Data Security Standard, a set of security requirements for credit card processors * Pro ...
bus is bridged onto the UMA with one slot available. It had a designer case and an internal modular construction. Two SCSI drives could be mounted on special caddies (1 in the later R10000/R12000 models due to heat constraints) and an optional video capture / sound cassette mounted on the far left side.


CPU

The O2 comes in two distinct CPU flavours; the low-end MIPS 180 to 350 MHz
R5000 The R5000 is a 64-bit, bi-endian, superscalar, in-order execution 2-issue design microprocessor, that implements the MIPS IV instruction set architecture (ISA) developed by Quantum Effect Design (QED) in 1996. The project was funded by MIPS Tec ...
- or RM7000-based units and the higher-end 150 to 400 MHz
R10000 The R10000, code-named "T5", is a RISC microprocessor implementation of the MIPS IV instruction set architecture (ISA) developed by MIPS Technologies, Inc. (MTI), then a division of Silicon Graphics, Inc. (SGI). The chief designers are Chris Rowe ...
- or
R12000 The R10000, code-named "T5", is a RISC microprocessor implementation of the MIPS IV instruction set architecture (ISA) developed by MIPS Technologies, Inc. (MTI), then a division of Silicon Graphics, Inc. (SGI). The chief designers are Chris Rowe ...
-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 hobbyis
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
SDRAM Synchronous dynamic random-access memory (synchronous dynamic RAM or SDRAM) is any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal. DRAM integrated circuits (ICs) produced from the ...
DIMM A DIMM () (Dual In-line Memory Module), commonly called a RAM stick, comprises a series of dynamic random-access memory integrated circuits. These memory modules are mounted on a printed circuit board and designed for use in personal compute ...
s. The Memory & Rendering Engine (MRE)
ASIC An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficien ...
contains the
memory controller The memory controller is a digital circuit that manages the flow of data going to and from the computer's main memory. A memory controller can be a separate chip or integrated into another chip, such as being placed on the same die or as an int ...
. Memory is accessed via a 133 MHz 144-bit bus, of which 128 bits are for data and the remaining for ECC. This bus is interfaced by a set of buffers to the 66 MHz 256-bit memory system.


I/O

I/O functionality is provided by the IO Engine ASIC. The ASIC provides a 64-bit
PCI PCI may refer to: Business and economics * Payment card industry, businesses associated with debit, credit, and other payment cards ** Payment Card Industry Data Security Standard, a set of security requirements for credit card processors * Pro ...
bus, an ISA bus, two
PS/2 port The PS/2 port is a 6-pin mini-DIN connector used for connecting keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mo ...
s for keyboard and mouse, and a 10/100 Base-T
Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
port. The PCI bus has one 64-bit slot, but the ISA bus is present solely for attaching a
Super I/O Super I/O is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a vari ...
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
CD-DA Compact Disc Digital Audio (CDDA or CD-DA), also known as Digital Audio Compact Disc or simply as Audio CD, is the standard format for audio compact discs. The standard is defined in the ''Red Book'', one of a series of Rainbow Books (named fo ...
mode other than Toshiba). Later units have Toshiba DVD-ROMs. The R5000/RM7000 units have two available drive sleds for
SCA SCA may refer to: Biology and health * Sickle cell disease, also known as sickle cell anaemia * Spinocerebellar ataxia, a neurological condition * Statistical coupling analysis, a method to identify covarying pairs of amino acids in protein mult ...
UltraWide SCSI hard-disks. Because the R10000/R12000 CPU module has a much higher cooling-fan assembly, the R10000/R12000 units have room for only one drive-sled.


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
OpenGL OpenGL (Open Graphics Library) is a cross-language, cross-platform application programming interface (API) for rendering 2D and 3D vector graphics. The API is typically used to interact with a graphics processing unit (GPU), to achieve hardwa ...
1.1 architecture with ARB image extensions in both software and hardware. The chipset consists of the microprocessor, and the ICE, MRE and Display ASICs. All
display list A display list (or ''display file'') is a series of graphics commands that define an output image. The image is created ( ''rendered'') by executing the commands to combine various primitives. This activity is most often performed by specialized di ...
and
vertex Vertex, vertices or vertexes may refer to: Science and technology Mathematics and computer science *Vertex (geometry), a point where two or more curves, lines, or edges meet * Vertex (computer graphics), a data structure that describes the positio ...
processing, as well as the control of the MRE ASIC is performed by the microprocessor. The ICE ASIC performs the packaging and unpacking of pixels as well as operations on pixel data. The MRE ASIC performs
rasterization In computer graphics, rasterisation (British English) or rasterization (American English) is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (a series of pixels, dots or lines, whic ...
and texture mapping. Due to the unified memory architecture, the texture and framebuffer memory comes from main memory, resulting in a system that has a variable amount of each memory. The Display Engine generates analog video signals from framebuffer data fetched from the memory for display.


Operating systems

Several
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
s support the O2: *
IRIX IRIX ( ) is a discontinued operating system developed by Silicon Graphics (SGI) to run on the company's proprietary MIPS workstations and servers. It is based on UNIX System V with BSD extensions. In IRIX, SGI originated the XFS file system and ...
6.3 or 6.5.x (native platform). *
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
port is working, but some drivers are missing. Both Gentoo and
Debian Debian (), also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software, developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of D ...
have releases that work on the O2. See th
IP32 port
page on linux-mips.org. *
OpenBSD OpenBSD is a security-focused, free and open-source, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD 1.0. According to the website, the OpenBSD project em ...
ran on the O2 starting from OpenBSD 3.7 until the discontinuation of the "sgi" port in OpenBSD 6.9. *
NetBSD NetBSD is a free and open-source Unix operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is a ...
has run on the O2 since NetBSD 2.0. It was the first
Open Source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
to be ported to the O2.NetBSD ported to SGI O2
/ref> See th
sgimips
port page.


Performance

The SGI O2 has an Imaging and Compression Engine (ICE)
application-specific integrated circuit An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficie ...
(ASIC) for processing
streaming media Streaming media is multimedia that is delivered and consumed in a continuous manner from a source, with little or no intermediate storage in network elements. ''Streaming'' refers to the delivery method of content, rather than the content it ...
and still images.Kilgard, Mark J. (1997). "Realizing OpenGL: Two implementations of one architecture". ''1997 SIGGRAPH/Eurographics Workshop'', pp. 45–55. ICE operates at 66 MHz and contains a
R3000 The R3000 is a 32-bit RISC microprocessor chipset developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture (ISA). Introduced in June 1988, it was the second MIPS implementation, succeeding the R2000 as the flag ...
-derived microprocessor serving as the scalar unit to which a 128-bit
SIMD Single instruction, multiple data (SIMD) is a type of parallel processing in Flynn's taxonomy. SIMD can be internal (part of the hardware design) and it can be directly accessible through an instruction set architecture (ISA), but it should ...
unit is attached using the MIPS coprocessor interface. ICE operates on eight 16-bit or sixteen 8-bit integers, but still provides a significant amount of computational power which enables the O2 to do video decoding and audio tasks that would require a much faster CPU if done without SIMD instructions. ICE only works with the IRIX operating system, as this is the only system that has drivers capable of taking advantage of this device. 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 Impact may refer to: * Impact (mechanics), a high force or shock (mechanics) over a short time period * Impact, Texas, a town in Taylor County, Texas, US Science and technology * Impact crater, a meteor crater caused by an impact event * Impac ...
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
Pentium Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and Pe ...
and AMD's K5).


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 Weather Star XL is the fifth generation of the WeatherStar systems used by the American cable and satellite television channel The Weather Channel (TWC), that are used to insert local forecasts and current weather information (such as the "Loc ...
computer for
The Weather Channel The Weather Channel (TWC) is an American pay television channel owned by Weather Group, LLC, a subsidiary of Allen Media Group. The channel's headquarters are in Atlanta, Georgia. Launched on May 2, 1982, the channel broadcasts weather forecas ...
* Desktop workstation * 3D modelling * Analogue video post-production * Defense industries


References


External links


SGIstuff: O2



SGI O2 Power Supply basics
{{Silicon Graphics O2 64-bit computers