SGI IRIS
| Company type | Product line |
|---|---|
| Industry | Computer workstations |
| Founded | 1983 |
| Founder | Silicon Graphics Computer Systems |
| Products | Workstations and terminals (IRIS 1000, IRIS 1200, IRIS 1400, IRIS 2000, IRIS 3000, 4D/60, Power IRIS, Personal IRIS, Indigo, Crimson) |
| Parent | Silicon Graphics |
The SGI IRIS lineup of workstations and terminals, developed by Silicon Graphics during the 1980s and 1990s, derives its name from Integrated Raster Imaging System.
68000
In November 1983, Silicon Graphics Computer Systems introduced its inaugural product, the IRIS 1000 terminal. This device incorporated hardware-accelerated 3D graphics powered by the Geometry Engine, a creation of Jim Clark and Marc Hannah at Stanford University. Rather than functioning as a standalone computer, it was designed to operate as a terminal connected to a VAX-11 running either VAX/VMS or Unix. The IRIS 1200 followed with an enhanced backplane, before SGI released the IRIS 1400 in 1984, marking their first independent workstation.
The initial models utilized the 'PM1' processor, a derivative of the SUN processor family, which included a Motorola 68000 or 68010 CPU running at 8 MHz. The IRIS 2000 series debuted in 1985 as SGI's first internally engineered system, featuring a Motorola 68010 clocked at 10 MHz. The last in the Motorola-based line, the IRIS 3000 launched in 1986, employed a Motorola 68020 processor operating at 16 MHz. These machines operated on GL1 and GL2 operating systems—early forerunners to the UNIX-oriented IRIX—with GL2 incorporating a proprietary windowing interface known as mex (Multiple EXposure).
MIPS
Beginning in 1987, SGCS transitioned to workstations powered by MIPS RISC processors, replacing the Motorola 680x0 series CPUs. These models were designated with a '4D/' prefix followed by two or three digits. The inaugural model, the 4D/60 'Professional IRIS', housed an MIPS R2300 running at 8 MHz within a distinctive twin-tower chassis. The larger left tower contained the card cage, while the smaller right tower held the power supply and drives; this right tower varied in height to accommodate additional storage. Similar to its predecessor, the IRIS 1000 series, the 4D/60 utilized a standard MIPS system board rather than a custom CPU board. Its initial operating system, '4D1', was largely based on MIPS' own RISC/OS.
In 1988, SGCS launched the Power IRIS line targeting high-end users with emphasis on SMP through proprietary POWERpath technology, alongside a more affordable Personal IRIS range. Power IRIS systems—later renamed "PowerSeries"—supported between one and eight processors and came in various form factors including twin-tower, mini-fridge ('Diehard'), and rack-mounted ('Predator') cases. Model numbers reflected CPU quantity via their second digit (for example, 4D/210 indicated one processor; 4D/340 denoted four processors). Eventually, Power IRIS was succeeded by the 64-bit MIPS R4000-based IRIS Crimson, followed by POWERpath-2 equipped Onyx and Challenge families.
The Personal IRIS collection comprised four variants: the 4D/20 and /25 released in 1988, and later the /30 and /35 models introduced in 1990. With prices starting around £10,300, these were Silicon Graphics’ most budget-friendly workstations. The 4D/35 model evolved into the IRIS Indigo workstation in 1991, sharing architectural features such as the Internal Processor ID (IP12).
From late 1992 onward with releases like the Indigo² and Challenge, SGI eliminated both the 'IRIS' branding and '4D/' model numbering. The operating system '4D1', officially known as IRIX 4D1 from version 4D1-3 onwards, was simplified to 'IRIX' starting with version 5. Despite this branding change, all subsequent MIPS-based SGI machines continued to use 'IRIS' as their default hostname up through the release of the Tezro in 2003.
Human Interface Devices
A distinctive characteristic shared among all IRIS variants—including 68K, Professional, Personal, PowerSeries, Indigo, and Crimson—is a unique serial communication protocol for keyboards and mice. Initial versions utilize DE-15 connectors (68K, Professional, PowerSeries) or DE-9 connectors (4D/20, 4D/25), whereas subsequent models such as the 4D/30, 4D/35, Indigo, Crimson, and Onyx adopt mini DIN-6 connectors, which are frequently confused with conventional PS/2 ports. It is important to note that attaching an IRIS keyboard to a PS/2 port or the reverse can cause hardware failure due to differing voltage specifications. A notable aspect of the IRIS interface—comparable to Apple’s Apple Desktop Bus and Sun’s serial interface—is the daisy-chained connection of the mouse through the keyboard.
See also
- Silicon Graphics Image for file extension
.iris - IRIS GL, the forerunner of OpenGL