The Cray Operating System (COS) is a

Cray Research Cray Inc., a subsidiary of Hewlett Packard Enterprise, is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

for its now-discontinued Cray-1 (1976) and Cray X-MP supercomputers. It succeeded the Chippewa Operating System (shipped with earlier Control Data Corporation CDC 6000 series and 7600 computer systems), and was the Cray main OS until replaced by

UNICOS UNICOS is a range of Unix and after it Linux operating system (OS) variants developed by Cray for its supercomputers. UNICOS is the successor of the Cray Operating System (COS). It provides network clustering and source code compatibility la ...

in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal.

Design

As COS was written by ex-

Control Data Control Data Corporation (CDC) was a mainframe and supercomputer firm. CDC was one of the nine major United States computer companies through most of the 1960s; the others were IBM, Burroughs Corporation, DEC, NCR, General Electric, Honeywell ...

employees, its command language and internal organization bore strong resemblance to the CDC SCOPE operating system on the CDC 7600 and before that EXEC*8 from CDC's earlier ERA/Univac pedigree. User jobs were submitted to COS via front-end computers via a high-speed channel interface, and so-called ''station software''. Front end stations were typically large IBM or

mainframes. However the

DEC VAX VAX (an acronym for Virtual Address eXtension) is a series of computers featuring a 32-bit instruction set architecture (ISA) and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century. The V ...

was also a very popular front-end. Interactive use of COS was possible through the stations, but most users simply submitted batch jobs. Disk-resident datasets used by a user program were 'local' to the individual job. Once a job completed, its local datasets would be released and space reclaimed. In order to retain the data between jobs, datasets had to be explicitly made 'permanent'.

Magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use mag ...

datasets were also supported on Cray systems which were equipped with an I/O Subsystem. COS also provided job scheduling and checkpoint/restart facilities to manage large workloads, even across system downtimes (both scheduled and unscheduled.) Internally, COS was divided into a very small message-passing EXEC, and a number of System Task Processors (STP tasks). Each STP task was similar in nature to the peripheral processor programs in earlier Control Data operating systems, but since the Cray machines did not have peripheral processors, the main central processor executed the operating system code.

List of STP tasks

While the source for version 1.13 was released as

public domain The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, ...

, 1.17 is available at archive.org.

References

1975 software Cray software Discontinued operating systems Supercomputer operating systems {{Operating-system-stub

Design

List of STP tasks

See also

References