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BESK (''Binär Elektronisk SekvensKalkylator'', 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 made for the University of Lund, ''SAABs räkneautomat'' 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 (Binär Aritmetisk Relä-Kalkylator, Swedish for "Binary Arithmetic Relay Calculator"). The team was initially led by Conny Palm, who died in December 1951, after which Stig Comét took over. The hardware was developed by Erik Stemme. Gösta Neovius and Olle Karlqvist were responsible for architecture and instruction set. It was closely modeled on the IAS machine for which the design team had retrieved drawings during a scholarship to Institute for Advanced Study (IAS) and Massachusetts Institute of Technology, U.S. During the development of the BESK magnetic Drum memory Olle Karlqvist discovered a magnetic phenomenon, which has been called the Karlqvist gap. ==Performance== BESK was a 40-bit machine; it could perform an addition in 56 μs and a multiplication took 350 μs. The electrostatic memory could store 512 words. The instruction length was 20 bits, so each word could store two instructions. BESK contained 2400 "radio tubes" (vacuum tubes) and 400 germanium diodes (so it was partly solid state). The power consumption was 15 kVA. Initially an average runtime of 5 minutes was achieved before hardware problems appeared. In 1954 the system became more stable. Breakpoints were introduced to allow software restart after hardware failures. Originally BESK had a British Williams tube 512 word x 40 bit memory based on 40 cathode tubes, and 8 spare tubes. The memory was from the beginning found to be insufficient and Carl-Ivar Bergman was given just a few weeks to build and install a ferrite core memory in 1956. To get finished before the deadline they hired housewives with knitting experience to make the memory. One of the new memory bits did not work at first, but it was easily cut out and replaced. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「BESK」の詳細全文を読む スポンサード リンク
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