Pyramid Technology

Pyramid Technology Corporation was a computer company that produced a number of RISC-based minicomputers at the upper end of the performance range. It was based in the San Francisco Bay Area of California

They also became the second company to ship a multiprocessor UNIX system (branded OSx), in 1985, which formed the basis of their product line into the early 1990s. Pyramid's OSx was a dual-universe UNIX which supported programs and system calls from both 4.xBSD and AT&T's UNIX System V.

Pyramid Technology was formed in 1981 by a number of ex-Hewlett-Packard employees, who were interested in building first-rate minicomputers based on RISC designs.

In March 1995 Pyramid was bought by Siemens AG and merged into their Siemens Computer Systems US unit. In 1998 this unit was split, with the services side of the operation becoming Wincor Nixdorf. In 1999 Siemens and Fujitsu merged their computer operations to form Fujitsu Siemens Computers, and finally Amdahl was added to the mix in 2000.

The first Pyramid Technology series of minicomputers was released in August 1983 as the 90x superminicomputer, which used their custom 32-bit scalar processor running at 8 MHz.

Although the architecture was marketed as a RISC machine, it was actually microprogrammed. It used a "sliding window" register model based on the Berkeley RISC processor, but memory access instructions had complex operation modes that could require many cycles to run. Many register-to-register scalar instructions were executed in a single machine cycle. Initially, floating point instructions were executed totally in microcode, although an optional floating point unit on a separate circuit board was released later. Microprogramming also allowed other non-RISC luxuries such as block move instructions.

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