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Cray Operating System

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This is an old revision of this page, as edited by NapoliRoma (talk | contribs) at 22:25, 22 May 2021 (clean up lead section -- I edited this to reflect what was written, but I have serious doubts about the points that this was a successor to Chippewa (the body indicates it was more a successor to SCOPE), and that it ever ran on CDC computers -- see talk). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Cray Operating System
DeveloperCray Research[1]
Working stateDiscontinued
Initial release1975; 50 years ago (1975)[1]
Latest release1.17.2 / July 1990; 35 years ago (1990-07)
Marketing targetSupercomputers
Available inEnglish
PlatformsCray-1, Cray X-MP line
LicenseProprietary

The Cray Operating System (COS) is a Cray Research operating system 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 in the late 1980s.[citation needed] COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal.

Design

As COS was written by ex-Control Data employees, its command language and internal organization bore strong resemblance to the 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 Control Data mainframes. However the DEC VAX 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 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

STP Task Description
DQM Disk Queue Manager
EXP User Exchange Processor
JCM Job Class Manager
JSH Job Scheduler
PDM Permanent Dataset Manager
SCP Station Call Processor
STARTUP Startup
TQM Tape Queue Manager

While the source for version 1.13 was released as public domain, 1.17 is available at archive.org.[2]

See also

References

  1. ^ a b T-0103C-CRAY_1_Computer_System-Operating_System_COS_Workbook-Training-15th September_1981
  2. ^ https://archive.org/details/Cos1.17DiskImageForCray-1x-mp
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