Dartmouth Time Sharing System
Encyclopedia
The Dartmouth Time-Sharing System, or DTSS for short, was the first large-scale time-sharing
system to be implemented successfully. DTSS was inspired by a PDP-1
-based time-sharing system at Bolt, Beranek and Newman
. In 1962, John Kemeny and Thomas Kurtz at Dartmouth College
submitted a grant for the development of a new time-sharing system to NSF
(funded in 1964). Its implementation began in 1963 by a student team under the direction of Kemeny and Kurtz with the aim of providing easy access to computing facilities for all members of the college. On May 1, 1964 at 4 AM the system began operations with the simulataneous where it remained so until the end of 1999. DTSS was originally implemented to run on a GE-200 series
computer with a GE Datanet 30 as a terminal processor that also managed the 235. Later, DTSS was reimplemented on the GE 635, still using the Datanet 30 for terminal control. The 635 version provided interactive time-sharing to up to nearly 300 simultaneous users in the 1970s, a very large number at the time.
Because of the educational aims, ease of use was a priority in DTSS design.
DTSS implemented the world's first Integrated Design Environment: a command-based system implementing the following commands.
These commands were often believed to be part of the Dartmouth BASIC
language by users but in fact they were part of the time sharing system and were also used when preparing ALGOL
or FORTRAN
programs via the DTSS terminals.
Any line typed in by the user, and beginning with a line number, was added to the program, replacing any previously stored line with the same number; anything else was immediately compiled and executed. Lines which consisted solely of a line number weren't stored but did remove any previously stored line with the same number. This method of editing provided a simple and easy to use service that allowed large numbers of teleprinter
s as the terminal units for the Dartmouth Timesharing system.
By 1968 and into the mid-1970s, the nascent network included users at other schools and institutions around the East Coast (including Goddard College
, Phillips Andover and the U.S. Naval Academy), connected with Teletype Model 33 machines and modems. The system allowed email-type messages to be passed between users and real-time chat via a precursor to the Unix
talk program.
In 2000 a project to recreate the DTSS system on a simulator was undertaken and as a result DTSS is now available for Microsoft Windows
systems and for the Apple Macintosh computer.
Time-sharing
Time-sharing is the sharing of a computing resource among many users by means of multiprogramming and multi-tasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major technological shift in the history of computing.By allowing a large...
system to be implemented successfully. DTSS was inspired by a PDP-1
PDP-1
The PDP-1 was the first computer in Digital Equipment Corporation's PDP series and was first produced in 1960. It is famous for being the computer most important in the creation of hacker culture at MIT, BBN and elsewhere...
-based time-sharing system at Bolt, Beranek and Newman
BBN Technologies
BBN Technologies is a high-technology company which provides research and development services. BBN is based next to Fresh Pond in Cambridge, Massachusetts, USA...
. In 1962, John Kemeny and Thomas Kurtz at Dartmouth College
Dartmouth College
Dartmouth College is a private, Ivy League university in Hanover, New Hampshire, United States. The institution comprises a liberal arts college, Dartmouth Medical School, Thayer School of Engineering, and the Tuck School of Business, as well as 19 graduate programs in the arts and sciences...
submitted a grant for the development of a new time-sharing system to NSF
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
(funded in 1964). Its implementation began in 1963 by a student team under the direction of Kemeny and Kurtz with the aim of providing easy access to computing facilities for all members of the college. On May 1, 1964 at 4 AM the system began operations with the simulataneous where it remained so until the end of 1999. DTSS was originally implemented to run on a GE-200 series
GE-200 series
The GE-200 series was a family of small mainframe computers of the 1960s, built by General Electric.The main machine in the line was the GE-225. It used a 20-bit word, of which 13 bits could be used for an address. Along with the basic CPU the system could also include a floating-point unit, or...
computer with a GE Datanet 30 as a terminal processor that also managed the 235. Later, DTSS was reimplemented on the GE 635, still using the Datanet 30 for terminal control. The 635 version provided interactive time-sharing to up to nearly 300 simultaneous users in the 1970s, a very large number at the time.
Because of the educational aims, ease of use was a priority in DTSS design.
DTSS implemented the world's first Integrated Design Environment: a command-based system implementing the following commands.
- NEW — to name and begin writing a program
- OLD — to retrieve a previously named program
- LIST — to display the current program
- SAVE — to save the current program
- RUN — to execute the current program
These commands were often believed to be part of the Dartmouth BASIC
Dartmouth BASIC
Dartmouth BASIC is the original version of the BASIC programming language. It is so named because it was designed and implemented at Dartmouth College...
language by users but in fact they were part of the time sharing system and were also used when preparing ALGOL
ALGOL
ALGOL is a family of imperative computer programming languages originally developed in the mid 1950s which greatly influenced many other languages and became the de facto way algorithms were described in textbooks and academic works for almost the next 30 years...
or FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
programs via the DTSS terminals.
Any line typed in by the user, and beginning with a line number, was added to the program, replacing any previously stored line with the same number; anything else was immediately compiled and executed. Lines which consisted solely of a line number weren't stored but did remove any previously stored line with the same number. This method of editing provided a simple and easy to use service that allowed large numbers of teleprinter
Teleprinter
A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...
s as the terminal units for the Dartmouth Timesharing system.
By 1968 and into the mid-1970s, the nascent network included users at other schools and institutions around the East Coast (including Goddard College
Goddard College
Goddard College is a private, liberal arts college located in Plainfield, Vermont, offering undergraduate and graduate degree programs. Goddard College currently operates on an intensive low-residency model...
, Phillips Andover and the U.S. Naval Academy), connected with Teletype Model 33 machines and modems. The system allowed email-type messages to be passed between users and real-time chat via a precursor to the Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
talk program.
In 2000 a project to recreate the DTSS system on a simulator was undertaken and as a result DTSS is now available for Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
systems and for the Apple Macintosh computer.