thumb|SGI Indigo, front

thumb|SGI Indigo, back

The Indigo, introduced as the IRIS Indigo, is a line of workstation computers developed and manufactured by Silicon Graphics, Inc. (SGI). SGI first announced the system in July 1991.

The Indigo is one of the most capable graphics workstations of its era, and was essentially peerless in the realm of hardware-accelerated three-dimensional graphics rendering. For use as a graphics workstation, the Indigo was equipped with a two-dimensional framebuffer or, for use as a 3D graphics workstation, with the Elan graphics subsystem including one to four Geometry Engines (GEs). SGI sold a server version with no video adapter.

The Indigo's design is based on a simple cube motif in indigo hue. Graphics and other peripheral expansions are accomplished via the GIO32 expansion bus.

The Indigo was superseded generally by the SGI Indigo2, and in the low-cost market segment by the SGI Indy.

Technical specifications

The first Indigo model (code-named Hollywood) was introduced on July 22, 1991. It is based on the IP12 processor board, which contains a 32-bit MIPS R3000A microprocessor soldered on the board and proprietary memory slots supporting up to 96 MB of RAM.

The later version (code-named Blackjack) was introduced in July 1992, priced from $, utilising a 64-bit MIPS R4000SC processor clocked externally at 50 MHz. The model is based on the IP20 processor board, which has a removable processor module (PM1 or PM2) containing a R4000 (100 MHz) or R4400 processor (100 MHz or 150 MHz) that implements the MIPS-III instruction set. The IP20 uses standard 72-pin SIMMs with parity, and has 12 SIMM slots for a total of 384 MB of RAM at maximum. comes in three versions. One version uses the system's GIO expansion bus. Another uses the main backplane like the XS, XZ, and Elan graphics options. The final is the same, but adds a second video output, giving the computer the ability to have two "heads", or monitors.

XS Graphics

The Indigo's XS Graphics option has a single GE7 Geometry Engine (GE), a RE3 Raster engine, a HQ2 Command engine, VC1, XMAP5. It is ideal for low-cost wireframe operations, compared to more powerful, and expensive options for textured graphics.

Operating system

The Indigo was designed to run IRIX, SGI's version of Unix.

SGI timeline

The Indigo was featured in Jurassic Park as the rendering system for Samuel L. Jackson's character Arnold and his station to render graphics for Park Control Systems. It was paired to a Macintosh Quadra 700.

References

  • IP12 - LinuxMIPS
  • Technolust: The Indigo Page (Silicon Graphics - SGI)
  • SGI Indigo / Silicon Graphics R4000 Architecture