The predecessor to the Indigo2 and Indy, the Indigo (Codename: "Blackjack," though it was also called the Song & Dance Machine and had a badge on the motherboard.) was Silicon Graphics (SGI) first desktop 3D graphics computer and was intended to replace the 4D series workstations. Considered by many SGI enthusiasts to be the best designed of the older SGI systems, it was first released around 1989/1990. Designed as a small tower, the Indigo was...indigo colored. It was able to use 5 types of graphics cards (Described Below) and supported 8MB-384MB of proprietory SIMM RAM (Must be in sets of 4, like 4 64MB sticks). The MIPS RISC CPUs availible were the R3000 and the R4000 (It is possible to use a R4400 150MHz on the Indigo. Also note that if you're planning to buy an R3000 Indigo, IRIX 5.2 is the last suppored version). It's bus architecture was SGI's own proprietory GIO-32 and had 3 3 1/2" drive bays with SCSI interface (I'll see if I can find specifics later).
Despite being the top of the line in 3D desktop development during its heyday. The Indigo finds little use in movies and other high profile businesses. However, many people love these things (I'd personally get one, but I went for an Indigo2...more economical) and are very unwilling to part with them. Still many can be found on eBay and can be purchased for around $70 or possibly less.
The Graphics Cards
- LG1 -- 8-bit color, software Z buffer, (1024x768)
- XS-8 -- 8-bit color, no Z buffer, 1 geometry engine (1280x1024, "EXPRESS*")
- XS-24 -- 24-bit color,no Z buffer, 1 geometry engine (1280x1024, "EXPRESS")
- XS-24Z -- 24-bit color, hardware Z-buffer, 1 geometry engine (1280x1024, "EXPRESS")
- XZ -- 24-bit color, hardware Z-buffer, 2 geometry engines (1280x1024, "EXPRESS")
- Elan: 24-bit color, hardware Z-buffer, 4 geometry engines (1280x1024, "EXPRESS")
* This was the type of graphics card SGI categorized them as.