The O2 is an entry-level Unix workstation introduced in 1996 by Silicon Graphics, Inc. (SGI) to replace their earlier Indy series.

Like the Indy, the O2 uses a single MIPS microprocessor and was intended to be used mainly for multimedia.

Memory is accessed via a 133 MHz 144-bit bus, of which 128 bits are for data and the remaining for ECC.

Because the R10000/R12000 CPU module has a much higher cooling-fan assembly, the R10000/R12000 units have room for only one drive-sled.

It was developed to be a low-cost implementation of the OpenGL 1.1 architecture with ARB image extensions in both software and hardware.

All display list and vertex processing, as well as the control of the MRE ASIC is performed by the microprocessor.

[4] ICE operates on eight 16-bit or sixteen 8-bit integers,[4] 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.

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.