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The Cray X-MP was a supercomputer designed, built and sold by Cray Research. The company's first parallel vector processor machine and a fourth generation super, it was the 1982 successor to the 1976 Cray-1, and the world's fastest computer 1983–1985. The principal designer was Steve Chen. __NOTOC__
Description
The X-MP shared the "horseshoe" design of the earlier machine and looked almost identical on the outside. The processors ran on a 9.5 nanosecond (105 MHz) clock (compared to 12.5 ns for the Cray-1A), delivering a theoretical peak speed of 200 megaflops per processor and 400 megaflops for the original two processor 1982 machine. Other improvements over the Cray-1 included: better chaining support and shared memory access with multiple memory ports per processor.
Cray Research continually enhanced the X-MP over the years. The X-MP/48 (1984) contained 4 cpus with theoretical system peak speed of over 800 megaflops. The X-MP/48 also introduced vector gather/scatter memory reference instructions to the product line. Clock speeds were improved to 8.5 ns (117 MHz), giving a per-cpu peak speed of over 230 MFlops. Memory sizes were also increased over time, culminating in the X-MP/EA series machines (1986) which offered the newer Cray Y-MP 32-bit memory addressing, instead of the older Cray-1 compatible 24-bit addressing.
The system initially ran the proprietary Cray Operating System (COS), with UniCOS (a UNIX System V derivation) running through the guest operating system facility. UniCOS became the main OS from 1986 onwards.
Configurations
The X-MP was sold with one, two, or four processors and from two to sixteen megawords (16–128 MB) of word-addressable RAM main memory (while initial memory capacity was limited to 16 megawords with a 24-bit address register, the later extended memory architecture XMP/EA raised addressable memory to a theoretical 2 gigawords, in practice the largest memory produced was 64 megawords. The XMP/EA had an 8.5 nanosecond clock), delivering a theoretical peak speed of 942 megaflops. A 1984 X-MP/48 was about States dollar|US$" target="_blank" >*15 million plus the cost of disks.
Image gallery
Successors
The Cray-2, a completely new design, was introduced 1985. A very different compact four-processor design with from 512 MB to 4 GB of main memory, it was specified to 500 megaflops but was slower than the X-MP on certain calculations due to its high memory latency. (In 1986 an X-MP/48 achieved a speed of 713 megaflops on the standardized LINPACK tests.)
The X-MP-succeeding Cray Y-MP series was sold from 1988; no radical design, it was an evolutionary improvement of the X-MP with up to eight redesigned processors.
Trivia
A horse-shoe shaped X-MP like computer acts as a furniture-prop for Robert Redford and Ben Kingsley in the hacker-thriller Sneakers.
"Cray X-MP"