ICT 1301
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The ICT 1301 and its smaller derivative ICT 1300 were early business
computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...
s from
International Computers and Tabulators International Computers and Tabulators or ICT was a British computer manufacturer, formed in 1959 by a merger of the British Tabulating Machine Company (BTM) and Powers-Samas. In 1963 it acquired the business computer divisions of Ferranti. It ...
. Typical of mid-sized machines of the era, they used
core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (laboratory), a highly specialized shared research resource * Core (manufacturing), used in casting and molding * Core (optical fiber), ...
, drum storage and
punched card A punched card (also punch card or punched-card) is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 18th to 20th centuries, punched cards were widel ...
s, but they were unusual in that they were based on decimal logic instead of
binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two values (0 and 1) for each digit * Binary function, a function that takes two arguments * Binary operation, a mathematical op ...
.


Description

The 1301 was the main machine in the line. Its
main memory Computer data storage or digital data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processin ...
came in increments of 400
words A word is a basic element of language that carries meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguists on its ...
of 48
bit The bit is the most basic unit of information in computing and digital communication. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as ...
s (12 decimal digits or 12 four-bit binary values, 0-15) plus two
parity bit A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes) ...
s. The maximum size was 4,000 words. It was the first ICT machine to use core memory. Backing store was magnetic drum and optionally one-inch-, half-inch- or quarter-inch-wide
magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...
. Input was from 80-column punched cards and optionally 160-column punched cards and
punched paper tape Punch commonly refers to: * Punch (combat), a strike made using the hand closed into a fist * Punch (drink), a wide assortment of drinks, non-alcoholic or alcoholic, generally containing fruit or fruit juice Punch may also refer to: Places * ...
. Output was to 80-column punched cards,
line printer A line printer Printer (computing), prints one entire line of text before advancing to another line. Most early line printers were printer (computing)#Impact printers, impact printers. Line printers are mostly associated with unit record eq ...
, and optionally to punched paper tape. The machine ran at a
clock speed Clock rate or clock speed in computing typically refers to the frequency at which the clock generator of a processor can generate pulses used to synchronize the operations of its components. It is used as an indicator of the processor's ...
of 1 MHz and its
arithmetic logic unit In computing, an arithmetic logic unit (ALU) is a Combinational logic, combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on ...
(ALU) operated on data in a ''serial-parallel'' fashion—the 48-bit words were processed sequentially four bits at a time. A simple addition took 21 clock cycles; hardware multiplication averaged 170 clock cycles per digit; and division was performed in software. A typical 1301 requires 700 square feet (65 square metres) of floor space and weighs about . It consumes about 13 kVA of
three-phase electric power Three-phase electric power (abbreviated 3Ï•) is a common type of alternating current (AC) used in electricity generation, transmission, and distribution. It is a type of polyphase system employing three wires (or four including an optional n ...
. The electronics consist of over 4,000
printed circuit board A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...
s each with many
germanium Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically ...
diode A diode is a two-Terminal (electronics), terminal electronic component that conducts electric current primarily in One-way traffic, one direction (asymmetric electrical conductance, conductance). It has low (ideally zero) Electrical resistance ...
s (mainly OA5), germanium
transistor A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...
s (mainly
Mullard Mullard Limited was a British manufacturer of electronics, electronic components. The Mullard Radio Valve Co. Ltd. of Southfields, London, was founded in 1920 by Captain Stanley R. Mullard, who had previously designed thermionic valves (US ...
GET872),
resistor A resistor is a passive two-terminal electronic component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active e ...
s,
capacitor In electrical engineering, a capacitor is a device that stores electrical energy by accumulating electric charges on two closely spaced surfaces that are insulated from each other. The capacitor was originally known as the condenser, a term st ...
s,
inductor An inductor, also called a coil, choke, or reactor, is a Passivity (engineering), passive two-terminal electronic component, electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typic ...
s, and a handful of thermionic valves and a few dozen
relay A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switc ...
s operated when buttons were pressed. Integrated circuits were not available commercially at the time.


History

The 1301 was designed by an ICT and GEC joint subsidiary, Computer Developments Limited (CDL) at GEC's
Coventry Coventry ( or rarely ) is a City status in the United Kingdom, cathedral city and metropolitan borough in the West Midlands (county), West Midlands county, in England, on the River Sherbourne. Coventry had been a large settlement for centurie ...
site formed in 1956. CDL was taken over by ICT, but the 1301 was built at the GEC site as ICT lacked the manufacturing capability at that time. The computer was announced in May 1960, though development had started much earlier. The first customer delivery was in 1962, a 1301 sold to the
University of London The University of London (UoL; abbreviated as Lond or more rarely Londin in Post-nominal letters, post-nominals) is a collegiate university, federal Public university, public research university located in London, England, United Kingdom. The ...
. One of their main attractions was that they performed British currency calculations ( pounds, shillings and pence) in hardware. They also had the advantage of programmers not having to learn
binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two values (0 and 1) for each digit * Binary function, a function that takes two arguments * Binary operation, a mathematical op ...
or
octal Octal (base 8) is a numeral system with eight as the base. In the decimal system, each place is a power of ten. For example: : \mathbf_ = \mathbf \times 10^1 + \mathbf \times 10^0 In the octal system, each place is a power of eight. For ex ...
arithmetic as the
instruction set In computer science, an instruction set architecture (ISA) is an abstract model that generally defines how software controls the CPU in a computer or a family of computers. A device or program that executes instructions described by that ISA, s ...
was pure decimal and the arithmetic unit had no binary mode, only decimal or pounds, shillings and pence. The London University machine was restored to working condition by a group of enthusiasts completing their task in 2012. Over 200 computers in the range were delivered, making it the best selling second generation British computer. Had the development been faster, it would have had more commercial potential.


Peripherals


Standard

The card reader could read 600 standard punched cards per minute, each with a capacity of up to 80 characters. The card punch could punch 100 cards per minute. The line printer could print 600 lines of 120 characters per minute. It used a print barrel made up of 120 print wheels each with 50 characters around its edge. Each of the 120 print positions had a print hammer which when fired squeezed the paper and an inked ribbon between itself and the rotating print barrel for a fraction of a second. It is reputed to be the first commercially produced barrel printer. A drum could record 12,000 words of data. It also had 400 words of 'reserved' storage where the computer's bootstrap program (then called Initial Orders) was stored. Up to 8 drums could be attached. Average access time was 5.7 ms.


Optional

The standard magnetic tape system (called tape type 3) used half-inch-wide (12.7 mm) magnetic tape with ten tracks at a density of 300 bits per inch. Four of the tracks held data, four more tracks held the inverse of the data and there was a
parity bit A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes) ...
for both groups of four. This allowed single-bit errors to be corrected and double-bit errors to be detected. Up to eight
Ampex Ampex Data Systems Corporation is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name ''AMPEX'' is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excell ...
TM4 tape decks, running at 75 inches per second for a throughput of 22,500 digits per second, could be connected. Spools could hold up to of tape and were of the three-prong design common at the time for professional audio recorders rather than the later industry standard expanding-hub design. The "High Speed" magnetic tape system (called tape type 1) used one-inch-wide (25.4 mm) magnetic tape running at 150 inches per second, with sixteen tracks at a density of 300 bits per inch. Eight of the tracks held data, with check data on the other eight, allowing single-bit errors to be corrected and double-bit errors to be detected. Up to eight tape decks could be connected, giving a throughput of 90,000 digits per second. Spools could hold up to of tape and were of three-prong design. There was also a system based on quarter-inch magnetic tape. This had a single write head and two read heads. The read heads were identical but each read from half of the width of the tape. Each digit was represented by two flux-reversal portions on the tape. The length of these segments determined the value of each digit. This meant that tape capacity was somewhat data dependent. The offcuts from damaged tape were compatible with the then normal audio tape recorders so there was a great deal of recycling. One or two paper-tape readers could be connected, each with a speed of 1,000 characters per second. A paper-tape punch of 300 characters per second was available. An online
teleprinter A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point (telecommunications), point-to-point and point- ...
was available, though very few machines had these. Towards the end of the life of the 1301, a single ICT standard interface could be added to allow data to be written to the by-then industry-standard magnetic tape.


ICT 1300

The ICT 1300 was identical to the 1301 in every way except that its card reader was limited to 300 cards per minute and its line printer was limited to 300 lines per minute. It tended to be sold with less core storage and drum storage and without magnetic tape. A drum with only a quarter of the read/write heads fitted was commonly used, giving 3,000 words of 48 bits as backing storage.


ICT 1302

The ICT 1302 was a larger version of the 1301 with the new ICT standard interface for connecting peripheral devices (the standard interface was later used on the
ICT 1900 series ICT 1900 was a family of mainframe computers released by International Computers and Tabulators (ICT) and later International Computers Limited (ICL) during the 1960s and 1970s. The 1900 series was notable for being one of the few non-America ...
).


Existing and restored ICT 1301s

Very few ICT 1301 computers remain in existence around the world, and of them, none is working. "Flossie" is the nickname given to an ICT 1301 () in storage at The National Museum of Computing at
Bletchley Park Bletchley Park is an English country house and Bletchley Park estate, estate in Bletchley, Milton Keynes (Buckinghamshire), that became the principal centre of Allies of World War II, Allied World War II cryptography, code-breaking during the S ...
, England. The computer had originally been used for computing exam results for students at the
University of London The University of London (UoL; abbreviated as Lond or more rarely Londin in Post-nominal letters, post-nominals) is a collegiate university, federal Public university, public research university located in London, England, United Kingdom. The ...
. After being restored and demonstrated in 2012, it was shut down and put in storage, and is to be restored again to operating condition. A second ICT 1301, which is close to operating condition, is on display at the Toitū Otago Settlers Museum in
Dunedin Dunedin ( ; ) is the second-most populous city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from ("fort of Edin"), the Scottish Gaelic name for Edinburgh, the capital of S ...
, New Zealand. This computer — the first in the city of Dunedin — was originally used by the
Cadbury Cadbury, formerly Cadbury's and Cadbury Schweppes, is a British multinational confectionery company owned by Mondelez International (spun off from Kraft Foods) since 2010. It is the second-largest confectionery brand in the world, after Mars. ...
confectionery factory for calculating invoices and payroll. There is a third machine named Arthur located in Cumbria, UK. The machine belongs to th
Time-Line Computer Archive museum
and although nearly complete, is not in working condition.Time-Line Computer Archive
, ''Simon Maltby'', 3 July 2014


References


External links



This is "Flossie" the original machine sold to London University.
YouTube video "Galdor Computing and the ICT1301" 26 minute description of machine and its adventures 1962 to 2015, by Stuart Fyfe 2021YouTube video of computer running a demonstration
Video of "Flossie" as she was in 2007.
3D Simulation of the ICT 1301Polish educational film (1967) about the basics of computer operation with ICT 1300 used as a prop
{{ICL hardware, 1301 1301 Transistorized computers Decimal computers Early British computers Computer-related introductions in 1962