The Cray-1 was a supercomputer designed by a team including Seymour Cray (who did the vector register technology) for Cray Research. The first Cray-1 system was installed at Los Alamos National Laboratory in 1976.

Description

The initial model the Cray-1A weighed 5.5 tons including the freon refrigeration system. The computer had a 'horseshoe' cross-section in order to reduce wire lengths within the casing; no wire in the system was more than four feet long (1.2 m). It used vector processors and contained 200,000 specialized ECL circuits. The CRAY-1A had a 12.5-nanosecond clock (80 MHz), 8 – 64-bit vector registers, and a high-speed word addressable memory of 1 million 64-bit words (8MB of RAM). It could produce two results per clock cycle leading to a theoretical peak performance of 160 million floating-point operations per second (160 MFLOPS).

The later Cray-1S had a faster clockspeed of 12.0-nanoseconds, and main memory in sizes of 1, 2 and 4 million words. There was an optional separate I/O subsystem connected to the main system via a 6MB per second control channel and a 100MB per second High Speed Data Channel, which offloaded the disk management from the main processor, and added support for IBM channel compatible tape drives.

Configured with 1 million words of RAM, the machine and its power supplies consumed about 115 KW of power; cooling and storage likely more than doubled this figure.

In 1978, the first standard software package for the Cray-1 was released, consisting of three main products:

• Cray Operating System (COS) (later machines would run UniCOS, Cray's UNIX flavour),
• Cray Assembler Language (CAL), and
• Cray FORTRAN (CFT), the first automatically vectorizing FORTRAN compiler

History

The National Center for Atmospheric Research (NCAR) was Cray Research's first official customer in July 1977, paying US$8.86 million ($7.9 million plus $1 million for the disks). The NCAR machine was decommissioned in January 1989. Priced from $5M to $8M, around 80 Cray-1s of all types were sold.

The Cray-1 was succeeded in 1982 by the 800 MFLOPS Cray X-MP, the first Cray multi-processing computer. In 1985 the very advanced Cray-2, capable of 1.9 GFLOPS peak performance, succeeded the two first models but met a somewhat limited commercial success because of certain problems at producing sustained performance in real-world applications. A more conservatively designed evolutionary successor of the Cray-1 and X-MP models was therefore made, by the name Cray Y-MP, and launched in 1988.

External links

• CRAY-1 Computer System Hardware Reference Manual, Publication No. 2240004 Rev.C 11/77 – first three chapters
  (from the copy at DigiBarn Computer Museum's [1] collection, digitized and HTML'ized by Ed Thelen)