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 i ...

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 daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

for the Cray-1 or Cray X-MP line of supercomputers. 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 (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 (LTSS) which ran on Control Data CDC 7600 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 forTRAN'', a FORTRAN 66 programming language but with dynamic memory and other features. The Cray version, including automatic vectorization, 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 producti ...

car of the period, for

Cray Vector Compiler 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 ...

. Some controversy existed at LASL with the first attempt to develop an operating system for the Cray-1 named

DEIMOS Deimos, a Greek word for ''dread'', may refer to: * Deimos (deity), one of the sons of Ares and Aphrodite in Greek mythology * Deimos (moon), the smaller and outermost of Mars' two natural satellites * Elecnor Deimos, a Spanish aerospace company * ...

, 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. 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 seri ...

) and their own vectorizing Fortran compiler named "CFT" ( Cray ForTran) 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 ...

(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 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 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 ...

(CUG) and the

ACM ACM or A.C.M. may refer to: Aviation * AGM-129 ACM, 1990–2012 USAF cruise missile * Air chief marshal * Air combat manoeuvring or dogfighting * Air cycle machine * Arica Airport (Colombia) (IATA: ACM), in Arica, Amazonas, Colombia Computing * ...

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