Cray X-MP

The Cray X-MP was a supercomputer designed, built and sold by Cray Research. It was announced in 1982 as the "cleaned up" successor to the 1975 Cray-1, and was the world's fastest computer from 1983 to 1985 with a quad-processor system performance of 800 MFLOPS. The principal designer was Steve Chen. The X-MP's main improvement over the Cray-1 was that it was a shared-memory parallel vector processor, the first such computer from Cray Research. It housed up to four CPUs in a mainframe that was nearly identical in outside appearance to the Cray-1. The X-MP CPU had a faster 9.5 nanosecond clock cycle (105 MHz), compared to 12.5 ns for the Cray-1A. It was built from bipolar gate-array integrated circuits containing 16 emitter-coupled logic (ECL) gates each. The CPU was very similar to the Cray-1 CPU in architecture, but had better memory bandwidth (with two read ports and one write port to the main memory instead of only one read/write port) and improved chaining support. Each CPU had a theoretical peak performance of 200 MFLOPS. The X-MP initially supported 2 million 64-bit words (16 MB) of main memory in 16 banks, respectively.