Cray Operating System
Encyclopedia
The Cray Operating System (COS) was Cray Research's proprietary operating system
for its Cray-1
(1976) and Cray X-MP
supercomputer
s, and those platforms' main OS until replaced by UNICOS
in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal
.
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.
However since the Cray machines did not have peripheral processors, the main central processor executed the operating system code.
While the source for version 1.13 was released as public domain
, there are no known saved copies, and thus COS is considered to be lost to time.
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
for its Cray-1
Cray-1
The Cray-1 was a supercomputer designed, manufactured, and marketed by Cray Research. The first Cray-1 system was installed at Los Alamos National Laboratory in 1976, and it went on to become one of the best known and most successful supercomputers in history...
(1976) and Cray X-MP
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...
supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
s, and those platforms' main OS until replaced by UNICOS
Unicos
UNICOS is the name of a range of Unix-like operating system variants developed by Cray for its supercomputers. UNICOS is the successor of the Cray Operating System . It provides network clustering and source code compatibility layers for some other Unixes. UNICOS was originally introduced in 1985...
in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal
Pascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object 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 7600CDC 7600
The CDC 7600 was the Seymour Cray-designed successor to the CDC 6600, extending Control Data's dominance of the supercomputer field into the 1970s. The 7600 ran at 36.4 MHz and had a 65 Kword primary memory using core and variable-size secondary memory...
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
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
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
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
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.
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 Control Program |
| STARTUP | Startup |
| TQM | Tape Queue Manager |
However since the Cray machines did not have peripheral processors, the main central processor executed the operating system code.
While the source for version 1.13 was released as public domain
Public domain
Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...
, there are no known saved copies, and thus COS is considered to be lost to time.
See also
- Cray Time Sharing SystemCray Time Sharing SystemThe Cray Time Sharing System, also known in the Cray user community as CTSS, was developed as an operating system for the Cray-1 or Cray X-MP line of supercomputers. CTSS was developed by the Los Alamos Scientific Laboratory in conjunction with the Lawrence Livermore Laboratory...
- Timeline of operating systems