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Carousel Memory
Carousel memory is a type of secondary storage for computers, which was created by Swedish computer engineers and Gunnar Stenudd. It was first shown at an exhibition in Paris in 1958. Description The FACIT ECM 64, manufactured by Swedish company Facit AB, is a prototype of carousel memory. To avoid having a single, long magnetic tape, it instead has 64 small rolls of each, with wide tape on each roll, divided into per roll. The tape speed is . To read a particular roll, the carousel rotates so the desired roll ends up at the bottom. A counterweight sits at the free end of the tape, and facilitates the roll in moving out and down into a mechanism with a read-and-write head. The tape is then rewound. The average seek time is and the storage space is . The control system is operated by transistors. Both the carousel and individual spools are replaceable. The magnetic tape is a 5/8-inch (1.6 cm) wide and 0.05 mm thick Mylar 3M Co type 188.The storage density is specified to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facit 1285 - Museum Of Technology In Warsaw - Poland
Facit (''Facit AB'') was an industrial corporation and manufacturer of office products including furniture. It was based in Åtvidaberg, Sweden, and founded in 1922 as ''AB Åtvidabergs Industrier''. Facit AB, a manufacturer of mechanical calculators, was incorporated into the corporation the same year. In 1932, the first ten-digit calculator was manufactured by Åtvidaberg Industries, it was named FACIT and became a great success. In the 1950s, Facit introduced a mascot character, a short, smiling man with a wizard's cap called "Facit Man". The character first appeared in the instruction manuals for Facit's calculators. The character lasted into the 1970s. By the early 1960s the corporation had a total of 8,000 employees with subsidiaries in over 100 countries, and the subsidiary Facit had come to dominate the business of the corporation. In 1965 the entire corporation changed its name to ''Facit AB''. The following year, it acquired its competitor '' Addo'', which was maintai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BoPET
BoPET (biaxially oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency reflectivity, and electrical insulation. When metallized, it has gas and moisture barrier properties. The film is "biaxially oriented", which means that the polymer chains are oriented parallel to the plane of the film, and therefore oriented over two axes. A variety of companies manufacture boPET and other polyester films under different brand names. In the UK and US, the best-known trade names are Mylar, Melinex, Lumirror and Hostaphan. It was the first biaxially oriented polymer to be manufactured on a mass commercial scale. History BoPET film was developed in the mid-1950s,Izard, Emmette Farr"Production of polyethylene terephthalate" U.S. patent no. 2,534,028 (filed: 1948 May 13; issued: 1950 December 12). originally by DuPont, Imperial Chemical In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZX Microdrive
ZX Microdrive unit The ZX Microdrive is a magnetic-tape data storage system launched in July 1983 by Sinclair Research for its ZX Spectrum home computer. It was proposed as a faster-loading alternative to the cassette and cheaper than a floppy disk, but it suffered from poor reliability and lower speed. Microdrives used tiny cartridges containing a endless loop of magnetic tape, which held a minimum of 85 KB and performed a complete circuit in approximately eight seconds. The Microdrive technology was later also used in the Sinclair QL and ICL One Per Desk personal computers. Development It is claimed the Microdrive concept was originally suggested by Andrew Grillet at an interview with Sinclair Research in 1974. Grillet was offered a better-paying job at Xerox, and never worked for Sinclair Research. Development of the ZX Microdrive hardware by Sinclair engineers Jim Westwood, David Southward and Ben Cheese started in 1982. Products Opened microdrive ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotronics Wafadrive
Wafadrive packaging Rotronics Wafadrive shown with two Wafa tapes, a blank 64 kB and software release tape Front and back of a Rotronics 64 kB Wafa tape The Rotronics Wafadrive is a magnetic tape storage peripheral launched in late 1984 for the ZX Spectrum home computer. Each tape is a continuous loop, unlike cassette tape. It was intended to compete with Sinclair's ZX Interface 1 and ZX Microdrive. The Wafadrive comprises two continuous loop stringy floppy tape drives, an RS-232 interface and Centronics parallel port. The drives can run at two speeds: High speed (for seeking) and low speed (for reading/writing, which was significantly slower than that of Microdrives). The cartridges (or "wafers"), the same as those used in Entrepo stringy floppy devices for other microcomputers, are physically larger than Microdrive cartridges. They were available in three different capacities, nominally 16 kB, 64 kB or 128 kB. The larger sizes had the disadvantag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karlqvist Gap
The Karlqvist gap or Karlqvist Field is an electromagnetic phenomenon discovered in 1953 by the Swedish engineer Olle Karlqvist (1922-1976), which is important in magnetic storage for computers. (HTML 1 kB) Karlqvist discovered the phenomenon while designing a ferromagnetic surface layer to the magnetic drum memory for the BESK computer. (HTML 3 kB) When designing a magnetic memory store, the ferromagnetic layer must be studied to determine the variation of the magnetic field with permeability, air gap, layer thickness and other influencing factors. The problem is non-linear and extremely difficult to solve. Karlqvist's gap discovery shows that the non-linear problem could be approximated by a linear boundary value for the two-dimensional static field and the one-dimensional transient field. This linear calculation gives a first approximation. Karlqvist published his discovery in the 1954 paper "Calculation of the magnetic field in ferromagnetic layer of a magnetic drum" at KTH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exatron Stringy Floppy
An Exatron Stringy Floppy (cover removed) designed for use with the TRS-80 Model 1 The Exatron Stringy Floppy (or ESF) is a continuous-loop tape drive developed by Exatron. History The company introduced an S-100 stringy floppy drive at the 1978 West Coast Computer Faire, and a version for the Radio Shack TRS-80 in 1979. Exatron sold about 4,000 TRS-80 drives by August 1981 for $249.50 each, stating that it was "our best seller by far". The tape cartridge is about the size of a business card, but about thick. The magnetic tape inside the cartridge is wide. Format There is no single catalog of files; to load a specific file the drive searches the entire tape, briefly stopping to read the header of each found file. The tape loop only moves in one direction, so a file that starts behind the current location cannot be read until the drive searches the entire loop for it. The device is capable of reading and writing random access data files (unlike a datacassette). If a re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BESK
BESK (''Binär Elektronisk SekvensKalkylator'', Swedish language, Swedish for "Binary Electronic Sequence Calculator") was Sweden's first electronic computer, using vacuum tubes instead of relays. It was developed by ''Matematikmaskinnämnden'' (Swedish Board for Computing Machinery) and for a short time it was the fastest computer in the world. The computer was completed in 1953 and in use until 1966. The technology behind BESK was later continued with the transistorized FACIT EDB and FACIT EDB-3 machines, both software compatible with BESK. Non-compatible machines highly inspired by BESK were SMIL (computer), SMIL made for the University of Lund, ''SAABs räkneautomat'' SARA (computer), SARA, "SAAB's calculating machine", and DASK made in Denmark. BESK was developed by the Swedish Board for Computing Machinery (Matematikmaskinnämnden) a few years after the mechanical relay computer BARK (computer), BARK (Binär Aritmetisk Relä-Kalkylator, Swedish for "Binary Arithmetic Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Västerås
Västerås () is a city in central Sweden on the shore of Mälaren, Lake Mälaren in the province of Västmanland, west of Stockholm. The city had a population of 127,799 at the end of 2019, out of the municipal total of 158,653, over 100,000 more than the next largest of the 17 localities included in the Västerås Municipality. Västerås is the seat of Västerås Municipality, which is the capital of Västmanland County and an episcopal see. History Västerås is one of the oldest cities in Sweden and Northern Europe. The area has been populated since the Nordic Viking Age, before 1000 CE. Anundshög, Sweden's largest burial mound, is located just outside the City of Västerås. It was built about 500 CE and is over wide and is almost high. In the beginning of the 11th century, Västerås was the second largest city in Sweden; by the 12th century, it had become the seat of the bishop. The name ''Västerås'' originates from ''Västra Aros'' (), first recorded as ''Westra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASEA
''Allmänna Svenska Elektriska Aktiebolaget'' ( English translation: General Swedish Electrical Limited Company; Swedish abbreviation: ASEA) was a Swedish industrial company. History ASEA was founded in 1883 by Ludvig Fredholm in Västerås as a manufacturer of electrical light and generators. After merging with Wenström's & Granström's Electrical Power Company (''Wenströms & Granströms Elektriska Kraftbolag'') the name was changed to ''Allmänna Svenska Elektriska Aktiebolaget'', literally the "General Swedish Electrical Limited Company", or ''ASEA'' for short. In 1987, it announced a merger with the Swiss company Brown, Boveri & Cie (BBC) to form ABB. The merge took effect on 1 January 1988.ASEA-BBC merger ''Modern Railways'' issue 472 January 1988 page 34 After this merger, ABB acquired several companies, including the power transmission and distribution operations of the Westinghouse Electric Corporation and the Combustion Engineering Group. *1889 – the partner J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FACIT EDB
FACIT EDB was a computer based on vacuum tubes that was manufactured by Åtvidabergs Industrier AB after the designs for BESK, that had been developed by the Swedish Board for Computing Machinery (Matematikmaskinnämnden). FACIT EDB was the first fully Swedish series production computer. EDB stod for "Electronic Computer Processing". The manufacturing was done by Åtvidabergs Industrier department of electronics in Stockholm and came to fruition by recruiting 18 key persons from the Swedish Board for Computing Machinery (Matematikmaskinnämndens). Internally nicknamed "the Besk boys". In 1960 the department became Facit Electronics with a new factory in Solna. The recruitment of people from Swedish Board for Computing Machinery were approved by the Finance minister Gunnar Sträng. That thought that production of computers was not something the government should be involved in. (HTML 12 kB) In 1963 a FACIT EDB-3 was installed at National Defence Radio Establishment (FRA) which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 semiconductor material, usually with at least three terminal (electronics), terminals for connection to an electronic circuit. A voltage or Electric current, current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more in miniature form are found embedded in integrated circuits. Because transistors are the key active components in practically all modern electronics, many people consider them one of the 20th century's greatest inventions. Physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transisto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
