Personal Iris

Silicon Graphics started the Personal Iris Series of machines with this model, the 4D/20. Powered by the then "new" MIPS 3000 RISC CPU (running at a staggering 12.5Mhz), it could take 16 or 32 megabytes of RAM, and contained an internal SCSI bus for a harddrive. It's strength over other Unix based workstations of the time was it's revolutionary graphics ability. The graphics processing was so powerful that very little work was actually done by the CPU. Providing real-time 24bit color, it was also capable of real-time polygon manipulation, making it a choice for CAD, realtime 3-D applications, virtual reality experiments, and of course, setting up and rendering 3-D sequences for movies like The Abyss, Terminator 2, and Jurrasic Park. Most of the Special Effects people working in Hollywood today cut their teeth on a machine like this one, creating some of the spectacular scenes we take for granted.

The second box for the "Iris File" is there to provide extra SCSI Vaults and does not contain any system boards. Instead of the boards the "Iris File" cases have 2 additional drivebays for 5.25" devices.

Computer World September 1990 Article on the Personal Iris 4D/25