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Synchronous Transmit-receive
Synchronous transmit-receive (STR) was an early IBM character-oriented communications protocol which preceded Bisync. STR was point-to-point only, and employed a ''four-of-eight'' transmission code, communicating at up to 5100 characters per second over half-duplex or full-duplex communication lines. The IBM 1009 Data Transmission Unit, the IBM 1130 Synchronous Communications Adapter, the IBM System/360 model 20 Communications Adapter, and the IBM 2701 Data Transmission Unit provided host computer support for STR. The IBM 7701, the IBM 7702 Magnetic Tape Transmission Terminal, the IBM 1013 Card Transmission Terminal, and the IBM 7710 and IBM 7711 Data Communication Units were among the remote devices supported by STR. STR was still supported as of 1972, although it had generally faded from use. Four-of-eight code The four-of-eight code was a 64 character set plus six control characters, encoded in eight bits. Like other kinds of 6b/8b encoding, exactly four bits of each ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Synchronous Communications
Binary Synchronous Communication (BSC or Bisync) is an IBM character-oriented, half-duplex link protocol, announced in 1967 after the introduction of System/360. It replaced the synchronous transmit-receive (STR) protocol used with second generation computers. The intent was that common link management rules could be used with three different character encodings for messages. Six-bit Transcode looked backwards to older systems; USASCII with 128 characters and EBCDIC with 256 characters looked forward. Transcode disappeared very quickly but the EBCDIC and USASCII dialects of Bisync continued in use. At one time Bisync was the most widely used communications protocol and is still in limited use in 2013. Framing Bisync differs from protocols that succeeded it in the complexity of message framing. Later protocols use a single framing scheme for all messages sent by the protocol. HDLC, Digital Data Communications Message Protocol (DDCMP), Point-to-Point Protocol (PPP), etc. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 1009
The IBM 1009 Data Transmission Unit was an IBM communications controller introduced in 1960. The 1009 used the Synchronous transmit-receive (STR) protocol to transfer data at 150 characters per second (cps) over a single point-to-point dial or leased telephone line. The system was advertised as being able to "link the magnetic core memories of IBM 1401 computers over telephone lines." The 1009 attached to IBM 1400 series computers such as the 1401 In 1961 the transmission rate was doubled to 300 cps. In 1962 the 1009 was part of a test of data communications using the Telstar satellite to link two 1401 computer systems. References External links Photo of a 1009 at the Computer History Museum 1009 Year 1009 ( MIX) was a common year starting on Saturday of the Julian calendar. Events By place Europe * February 14 or March 9 – The first known mention is made of the name of Lithuania, in connection with the murder of Bruno ... IBM transistorized compute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 1130
The IBM 1130 Computing System, introduced in 1965, was IBM's least expensive computer at that time. A binary 16-bit machine, it was marketed to price-sensitive, computing-intensive technical markets, like education and engineering, succeeding the decimal IBM 1620 in that market segment. Typical installations included a 1 megabyte disk drive that stored the operating system, compilers and object programs, with program source generated and maintained on punched cards. Fortran was the most common programming language used, but several others, including APL, were available. The 1130 was also used as an intelligent front-end for attaching an IBM 2250 Graphics Display Unit, or as remote job entry (RJE) workstation, connected to a System/360 mainframe. Description The total production run of the 1130 has been estimated at 10,000. The 1130 holds a place in computing history because it (and its non-IBM clones) gave many people their first direct interaction with a computer. Its pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System/360
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 System/360 family introduced IBM's Solid Logic Technology (SLT), which packed more transistors onto a circuit card, allowing more powerful but smaller computers to be built. The slowest System/360 model announced in 1964, the Model 30, could perform up to 34,500 instructions per second, with memo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 270x
270x is a generic name for a family of IBM non-programmable communications controllers used with System/360 and System/370 computers. The family consisted of the following devices: * IBM 2701 Data Adapter Unit * IBM 2702 Transmission Control * IBM 2703 Transmission Control The 2701 and 2702 were announced simultaneously with System/360 in 1964, the 2703 was announced a year later. The 270x series was superseded by the IBM 3704 and 3705 communications controllers in 1972. 2701 The 2701 supported up to four start-stop or synchronous communications lines. It had two multiplexor channel interfaces for connection to one or two host computers. The synchronous adapter originally supported the ''Synchronous Transmit-Receive (STR)'' protocol, and later ''Binary Synchronous Communications (BISYNC)'' when it was introduced in 1967, in half duplex mode at speeds of up to 40,800 bits per second (bit/s). The 2701 could also have "data acquisition and control adapt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 7701
The IBM 7701 Magnetic Tape Transmission Terminal was a communications device announced by IBM in 1960. It was designed to transfer the contents of a reel of magnetic tape over a leased or dial telephone circuit. The IBM 7702 was a similar device that could communicate at higher speeds. The 7701 was the first product introduced in conjunction with IBM's ''TELE-PROCESSING'' trademark. Technical details The 7701 communicated using the Synchronous transmit-receive Synchronous transmit-receive (STR) was an early IBM character-oriented communications protocol which preceded Bisync. STR was point-to-point only, and employed a ''four-of-eight'' transmission code, communicating at up to 5100 characters per sec ... (STR) communications protocol over either private or switched (''message service'') telephone lines. It operated at speeds of either 75 or 150 characters per second (cps). The 7702 operated at speeds of either 150, 250, or 300 characters per second. The devices used a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 7702
The IBM 7701 Magnetic Tape Transmission Terminal was a communications device announced by IBM in 1960. It was designed to transfer the contents of a reel of magnetic tape over a leased or dial telephone circuit. The IBM 7702 was a similar device that could communicate at higher speeds. The 7701 was the first product introduced in conjunction with IBM's ''TELE-PROCESSING'' trademark. Technical details The 7701 communicated using the Synchronous transmit-receive Synchronous transmit-receive (STR) was an early IBM character-oriented communications protocol which preceded Bisync. STR was point-to-point only, and employed a ''four-of-eight'' transmission code, communicating at up to 5100 characters per sec ... (STR) communications protocol over either private or switched (''message service'') telephone lines. It operated at speeds of either 75 or 150 characters per second (cps). The 7702 operated at speeds of either 150, 250, or 300 characters per second. The devices used a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 1013
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The IBM 1013 Card Transmission Terminal was a device manufactured by IBM from 1961 which transmitted the data held on 80-column cards to a remote computer or another 1013. The speed was generally considered 100 cards per minute but could be faster if programmed to send/receive only a portion of the cards if all 80 columns were not used. It needed a full-duplex circuit to operate but at any given time could only transmit or receive. References External links "IBM 1013 Card Transmission Terminal / Communicating Reader-Punch"at Computer History Museum 1013 1013 Year in topic Year 1013 ( MXIII) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. Events By place Europe * King Henry II of Germany signs a peace treaty at Merseburg with Duke Boles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6b/8b Encoding
In telecommunications, 6b/8b is a line code that expands 6-bit codes to 8-bit symbols for the purposes of maintaining DC-balance in a communications system. The 6b/8b encoding is a balanced code -- each 8-bit output symbol contains 4 zero bits and 4 one bits. So the code can, like a parity bit, detect all single-bit errors. The number of 8-bit patterns with 4 bits set is the binomial coefficient \tbinom 84 = 70. Further excluding the patterns 11110000 and 00001111, this allows 68 coded patterns: 64 data codes, plus 4 additional control codes. Coding rules The 64 possible 6-bit input codes can be classified according to their disparity, the number of 1 bits minus the number of 0 bits: The 6-bit input codes are mapped to 8-bit output symbols as follows: * The 20 6-bit codes with disparity 0 are prefixed with 10''Example: 000111 → 10000111''''Example: 101010 → 10101010'' * The 15 6-bit codes with disparity +2, other than 001111, are prefixed with 00''Example: 010111 → 0001 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EBCDIC
Extended Binary Coded Decimal Interchange Code (EBCDIC; ) is an eight-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems. It descended from the code used with punched cards and the corresponding six-bit binary-coded decimal code used with most of IBM's computer peripherals of the late 1950s and early 1960s. It is supported by various non-IBM platforms, such as Fujitsu-Siemens' BS2000/OSD, OS-IV, MSP, and MSP-EX, the SDS Sigma series, Unisys VS/9, Unisys MCP and ICL VME. History EBCDIC was devised in 1963 and 1964 by IBM and was announced with the release of the IBM System/360 line of mainframe computers. It is an eight-bit character encoding, developed separately from the seven-bit ASCII encoding scheme. It was created to extend the existing Binary-Coded Decimal (BCD) Interchange Code, or BCDIC, which itself was devised as an efficient means of encoding the two ''zone'' and ''number'' punches on punched cards into six bits. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
