packet switching
In telecommunications, packet switching is a method of grouping data into '' packets'' that are transmitted over a digital network. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the p ...
network
Network, networking and networked may refer to:
Science and technology
* Network theory, the study of graphs as a representation of relations between discrete objects
* Network science, an academic field that studies complex networks
Mathematic ...
written by
I. P. Sharp Associates
I. P. Sharp Associates (IPSA) was a major Canadian computer time-sharing, consulting and services firm of the 1970s and 1980s. IPSA is well known for its work on the programming language APL, an early packet switching computer network named IPS ...
(IPSA). Operation began in May 1976. It initially used the
IBM 3705 Communications Controller
The IBM 3705 Communications Controller is a simple computer which attaches to an IBM System/360 or System/370. Its purpose is to connect communication lines to the mainframe channel. It was a first communications controller of the popular IBM 3 ...
and
Computer Automation
Computer Automation Inc. was a computer manufacturer founded by David H. Methvin in 1968, based originally in Newport Beach, California, United States.Datamation, June 1968 p.167 It opened a sales, support and repair arm in the UK in 1972, bas ...
node
In general, a node is a localized swelling (a " knot") or a point of intersection (a vertex).
Node may refer to:
In mathematics
* Vertex (graph theory), a vertex in a mathematical graph
* Vertex (geometry), a point where two or more curves, line ...
s. An
Intel 80286
The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non- multiplexed address and data buses and also the ...
based-node was added in 1987. It was called the Beta node.
The original purpose was to connect low-speed
dumb terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal a ...
s to a central
time sharing
In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1
Its emergence ...
host in Toronto. It was soon modified to allow a terminal to connect to an alternate host running the
SHARP APL
Sharp or SHARP may refer to:
Acronyms
* SHARP (helmet ratings) (Safety Helmet Assessment and Rating Programme), a British motorcycle helmet safety rating scheme
* Self Help Addiction Recovery Program, a charitable organisation founded in 199 ...
software under license. Terminals were initially either 2741-type machines based on the 14.8 characters/s
IBM Selectric typewriter
The IBM Selectric typewriter was a highly successful line of electric typewriters introduced by IBM on 31 July 1961.
Instead of the "basket" of individual typebars that swung up to strike the ribbon and page in a typical typewriter of the peri ...
or 30 character/s ASCII machines. Link speed was limited to 9600 bit/s until about 1984.
Other services including 2780/3780Bisync support, remote printing,
X.25
X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN). It was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts a ...
gateway and SDLC pipe lines were added in the 1978 to 1984 era. There was no general purpose data transport facility until the introduction of ''Network Shared Variable Processor'' (NSVP) in 1984. This allowed APL programs running on different hosts to communicate via
Shared Variables Shared Variables are a feature of the programming language APL which allows APL programs running on one processor to share information with another processor. Although originally developed for mainframe computers, Shared Variables were also used i ...
.
The Beta node improved performance and provided new services not tied to APL. An
X.25
X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN). It was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts a ...
interface was the most important of these. It allowed connection to a host which was not running SHARP APL.
IPSANET allowed for the development of an early yet advanced
e-mail
Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic (digital) version of, or counterpart to, mail, at a time when "mail" meant ...
service, ''666 BOX'', which also became a major product for some time, originally hosted on IPSA's system, and later sold to end users to run on their own machines. NSVP allowed these remote e-mail systems to exchange traffic.
The network reached its maximum size of about 300 nodes before it was shut down in 1993.