The Cray Time Sharing System, also known in the

Cray 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 ...

user community as CTSS, was developed as an

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

for the

Cray-1 The Cray-1 was a supercomputer designed, manufactured and marketed by Cray Research. Announced in 1975, the first Cray-1 system was installed at Los Alamos National Laboratory in 1976. Eventually, over 100 Cray-1s were sold, making it one of the ...

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 with a quad-processor system performance ...

line of

supercomputer A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions ...

s. CTSS was developed by the

Los Alamos Scientific Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, in ...

(LASL now LANL) in conjunction with the

Lawrence Livermore Laboratory Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response ...

(LLL now LLNL). CTSS was popular with Cray sites in the

United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United Stat ...

(DOE), but was used by several other Cray sites, such as the San Diego Supercomputing Center.

Overview

The predecessor of CTSS was the

Livermore Time Sharing System The Livermore Time Sharing System (LTSS) was a supercomputer operating system originally developed by the Lawrence Livermore Laboratories for the Control Data Corporation 6600 and 7600 series of supercomputers. LTSS resulted in the Cray Time ...

(LTSS) which ran on Control Data

CDC 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 (27.5 ns clock cycle) and had a 65 Kword primary memory (with a 6 ...

line of supercomputers. The first

compiler In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...

was known as ''LRLTRAN'', for ''

Lawrence Radiation Laboratory Lawrence may refer to: Education Colleges and universities * Lawrence Technological University, a university in Southfield, Michigan, United States * Lawrence University, a liberal arts university in Appleton, Wisconsin, United States Preparator ...

forTRAN'', a FORTRAN 66 programming language but with

dynamic memory Memory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when ...

and other features. The Cray version, including

automatic vectorization Automatic vectorization, in parallel computing, is a special case of automatic parallelization, where a computer program is converted from a scalar implementation, which processes a single pair of operands at a time, to a vector implementation, ...

, was known as CVC, pronounced "Civic" like the

Honda is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan. Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...

car of the period, for Cray Vector Compiler. Some controversy existed at LASL with the first attempt to develop an operating system for the Cray-1 named DEIMOS, a message-passing,

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

operating system, by

Forrest Basket Forrest may refer to: Places Australia *Forrest, Australian Capital Territory *Forrest, Victoria, a small rural township * Division of Forrest, a federal division of the Australian House of Representatives, in Western Australia *Electoral distri ...

. DEIMOS had initial "teething" problems common to the performance of all early operating systems. This left a bad taste for Unix-like systems at the National Laboratories and with the manufacturer, Cray Research, Inc., of the hardware who went on to develop their own batch oriented operating system, COS (

Cray Operating System 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 a ...

) and their own vectorizing Fortran compiler named "CFT" (

Cray ForTran 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 i ...

) both written in the

Cray Assembly Language 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 i ...

(CAL). CTSS had the misfortune to have certain constants, structures, and lacking certain networking facilities (

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

) which were optimized to be Cray-1 architecture-dependent without extensive rework when larger memory supercomputers like the Cray-2 and the Cray Y-MP came into use. CTSS has its final breaths running on Cray instruction-set-compatible hardware developed by Scientific Computer Systems (SCS-40 and SCS-30) and

Supertek Supertek Computers Inc. was a computer company founded in Santa Clara, California in 1985 by Mike Fung, an ex-Hewlett-Packard project manager, with the aim of designing and selling low-cost minisupercomputers compatible with those from Cray Resea ...

S-1, but this did not save the software. CTSS embodied certain unique ideas such as a market-driven priorities for working/running processes. An attempt to succeed CTSS was started by LLNL named NLTSS ( New Livermore Time Sharing System) to embody advanced concepts for operating systems to better integrate communication using a new network protocol named LINCS while also keeping the best features of CTSS. NLTSS followed the development fate of many operating systems and only briefly ran on period Cray hardware of the late 1980s. A user-level CTSS Overview
CTSS Overview, LA-5525-M, Vol 7 from 1982 provides, in Chapter 2, a brief list of CTSS features. Other references are likely to be found in proceedings of the Cray User Group (CUG) and the ACM SOSP (Symp. on Operating Systems Proceedings). However, owing to the fact that LANL and LLNL were nuclear weapons facilities, some aspects of security are likely to doom finding out greater detail of many of these pieces of software.

References

{{Time-sharing operating systems Cray software Fortran software Time-sharing operating systems Proprietary operating systems Supercomputer operating systems

Overview

See also

References