The bit is the most basic unit of information in computing and digital communications. 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 either "1" or "0", but other representations such as true/false, yes/no, on/off, or +/− are also commonly used.
The IBM System/360 (S/360) is a family of mainframe computer systems that was announced by IBM on April 7, 1964, and delivered between 1965 and 1978. It was the first family of computers designed to cover both commercial and scientific applications and to cover a complete range of applications from small to large. The design distinguished between architecture and implementation, allowing IBM to release a suite of compatible designs at different prices. All but the only partially compatible Model 44 and the most expensive systems use microcode to implement the instruction set, which features 8-bit byte addressing and binary, decimal, and hexadecimal floating-point calculations.
The IBM 1620 was announced by IBM on October 21, 1959, and marketed as an inexpensive scientific computer. After a total production of about two thousand machines, it was withdrawn on November 19, 1970. Modified versions of the 1620 were used as the CPU of the IBM 1710 and IBM 1720 Industrial Process Control Systems.
The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the first computer to make a meaningful profit. The first one was installed in late 1954 and it was the most-popular computer of the 1950s.
Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria. Drums were widely used in the 1950s and into the 1960s as computer memory.
The UNIVAC Solid State was a magnetic drum-based solid-state computer announced by Sperry Rand in December 1958 as a response to the IBM 650. It was one of the first computers to be (nearly) entirely solid-state, using 700 transistors, and 3000 magnetic amplifiers (FERRACTOR) for primary logic, and 20 vacuum tubes largely for power control. It came in two versions, the Solid State 80 and the Solid State 90. In addition to the "80/90" designation, there were two variants of the Solid State – the SS I 80/90 and the SS II 80/90. The SS II series included two enhancements – the addition of 1,280 words of core memory and support for magnetic tape drives. The SS I had only the standard 5,000-word drum memory described in this article and no tape drives.
The DEUCE was one of the earliest British commercially available computers, built by English Electric from 1955. It was the production version of the Pilot ACE, itself a cut-down version of Alan Turing's ACE.
The Z4 was arguably the world's first commercial digital computer. It was designed, and manufactured by early computer scientist Konrad Zuse's company Zuse Apparatebau, for an order placed by Henschel & Son, in 1942; though only partially assembled in Berlin, then completed in Göttingen, and not delivered by the defeat of Nazi Germany, in 1945. The Z4 was Zuse's final target for the Z3 design. Like the earlier Z2, it comprised a combination of mechanical memory and electromechanical logic, so was not a true electronic computer.
The Z22 was the seventh computer model Konrad Zuse developed. One of the early commercial computers, the Z22's design was finished about 1955. The major version jump from Z11 to Z22 was due to the use of vacuum tubes, as opposed to the electromechanical systems used in earlier models. The first machines built were shipped to Berlin and Aachen.
The Bendix G-15 is a computer introduced in 1956 by the Bendix Corporation, Computer Division, Los Angeles, California. It is about 5 by 3 by 3 feet and weighs about 966 pounds (438 kg). The G-15 has a drum memory of 2,160 29-bit words, along with 20 words used for special purposes and rapid-access storage. The base system, without peripherals, cost $49,500. A working model cost around $60,000. It could also be rented for $1,485 per month. It was meant for scientific and industrial markets. The series was gradually discontinued when Control Data Corporation took over the Bendix computer division in 1963.
The ICT 1301 and its smaller derivative ICT 1300 were early business computers from International Computers and Tabulators. Typical of mid-sized machines of the era, they used core memory, drum storage and punched cards, but they were unusual in that they were based on decimal logic instead of binary.
The ZEBRA was one of the first computers to be designed in the Netherlands, and one of the first Dutch computers to be commercially available. It was designed by Willem van der Poel of the Netherlands Post, Telegraph and Telephone, and first delivered in 1958. The production run consisted of fifty-five machines, manufactured and marketed by the British company Standard Telephones and Cables, Ltd.
The NCR 315 Data Processing System, released in January 1962 by NCR, is a second-generation computer. All printed circuit boards use resistor–transistor logic (RTL) to create the various logic elements. It uses 12-bit slab memory structure using magnetic-core memory. The instructions can use a memory slab as either two 6-bit alphanumeric characters or as three 4-bit BCD digits. Basic memory is 5000 "slabs" of handmade core memory, which is expandable to a maximum of 40,000 slabs in four refrigerator-size cabinets. The main processor includes three cabinets and a console section that houses the power supply, keyboard, output writer, and a panel with lights that indicate the current status of the program counter, registers, arithmetic accumulator, and system errors. Input/Output is by direct parallel connections to each type of peripheral through a two-cable bundle with 1-inch-thick cables. Some devices like magnetic tape and the CRAM are daisy-chained to allow multiple drives to be connected.
The RCA Spectra 70 was a line of electronic data processing (EDP) equipment manufactured by the Radio Corporation of America’s computer division beginning in April 1965. The Spectra 70 line included several CPU models, various configurations of core memory, mass-storage devices, terminal equipment, and a variety of specialized interface equipment.
The Bendix G-20 computer was introduced in 1961 by the Bendix Corporation, Computer Division, Los Angeles, California. The G-20 followed the highly successful G-15 vacuum-tube computer. Bendix sold its computer division to Control Data Corporation in 1963, effectively terminating the G-20.
The DATANET-30, or DN-30 for short, was a computer manufactured by General Electric designed in 1961-1963 to be used as a communications computer. It was later used as a front-end processor for data communications. It became the first front end communications computer. The names on the patent were Don Birmingham, Bob McKenzie, Bud Pine, and Bill Hill.
The Monroe Calculating Machine Mark XI was a general-purpose stored-program electronic digital computer introduced in 1960 by the Monroe Calculating Machine Division of Litton Industries. The system was marketed for "primarily for billing, and invoice writing", but could also be used for low-end scientific computing.
The Zuse Z23 was a transistorized computer first delivered in 1961, designed by the Zuse KG company. A total of 98 units were sold to commercial and academic customers up until 1967. It had a 40-bit word length and used an 8192 word drum memory as main storage, with 256 words of rapid-access ferrite memory. It operated on fixed and floating-point binary numbers. Fixed-point addition took 0.3 milliseconds, a fixed point multiplication took 10.3 milliseconds. It was similar in internal design to the earlier vacuum tube Z22. Related variants were the Z25 and Z26 models.
The ERMETH was one of the first computers in Europe and was developed and built by Eduard Stiefel and his team of the Institute for Applied Mathematics at the ETH Zurich between 1948 and 1956. It was in use until 1963 and is now displayed at the Museum of Communication Bern (Switzerland).
A track is a path on a recording medium. There are some variations in nomenclature; for some media a track is a logical path and for others it is based on the geometry of the medium. The term is not used for punched cards.
