|
IBM Transcode
Six-Bit Transcode, or Six-Bit Transmission Code, was, for a few years, one of the three character sets used by IBM for Binary Synchronous Communications. Transmission using 6-bit Transcode had higher throughput than transmission using 8-bit EBCDIC or ASCII, provided that the data to be transmitted used a limited set of 48 characters. The IBM 2780 data transmission terminal was announced with Transcode support in 1967. Its successor, the IBM 3780 data communication terminal, announced in 1972, dropped Transcode support and added a "space compression" option. Transcode is a six-bit character code. It relates to IBM's punched card code but, like EBCDIC, it is not BCD. Its 64 values consist of the 26 uppercase letters, 10 numbers, 11 symbols, space, and 16 control characters. Its 48 printable characters are ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 .'-/@#$%&*⌑; it cannot represent ,:;!?"()[]+^=_\`, ~. Characters are transmitted with odd parity. The 2780 cannot use the 16 control cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Character Encoding
Character encoding is the process of assigning numbers to Graphics, graphical character (computing), characters, especially the written characters of Language, human language, allowing them to be Data storage, stored, Data communication, transmitted, and Computing, transformed using Digital electronics, digital computers. The numerical values that make up a character encoding are known as "code points" and collectively comprise a "code space", a "code page", or a "Character Map (Windows), character map". Early character codes associated with the optical or electrical Telegraphy, telegraph could only represent a subset of the characters used in written languages, sometimes restricted to Letter case, upper case letters, Numeral system, numerals and some punctuation only. The low cost of digital representation of data in modern computer systems allows more elaborate character codes (such as Unicode) which represent most of the characters used in many written languages. Character enc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterisk
The asterisk ( ), from Late Latin , from Ancient Greek , ''asteriskos'', "little star", is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star. Computer scientists and mathematicians often vocalize it as star (as, for example, in ''the A* search algorithm'' or '' C*-algebra''). In English, an asterisk is usually five- or six-pointed in sans-serif typefaces, six-pointed in serif typefaces, and six- or eight-pointed when handwritten. Its most common use is to call out a footnote. It is also often used to censor offensive words. In computer science, the asterisk is commonly used as a wildcard character, or to denote pointers, repetition, or multiplication. History The asterisk has already been used as a symbol in ice age cave paintings. There is also a two thousand-year-old character used by Aristarchus of Samothrace called the , , which he used when proofreading Homeric poetry to mark lines that were duplicated. Origen is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System/370
The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the product announcement. In September 1990, the System/370 line was replaced with the System/390. Evolution The original System/370 line was announced on June 30, 1970, with first customer shipment of the Models 155 and 165 planned for February 1971 and April 1971 respectively. The 155 first shipped in January 1971. System/370 underwent several architectural improvements during its roughly 20-year lifetime. The following features mentioned in Principles of Operation are either optional on S/360 but standard on S/370, introduced with S/370 or added to S/370 after announcement. *Branch and Save *Channel Indirect Data Addressing *Channel-Set Switching *Clear I/O *C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 2780/3780
The IBM 2780 and the IBM 3780 are devices developed by IBM to perform remote job entry (RJE) and other batch functions over telephone lines; they communicate with the mainframe via Binary Synchronous Communications (BSC or Bisync) and replaced older terminals using synchronous transmit-receive (STR). In addition, IBM has developed workstation programs for the 1130, 360/20, 2922, System/360 other than 360/20, System/370 and System/3. 2780 Data Transmission Terminals The 2780 Data Transmission Terminal first shipped in 1967. It consists of: * A line printer similar to the IBM 1443 that can print up to 240 lines per minute (lpm), or 300 lpm using an extremely restricted character set. * A card reader/punch unit, similar to an IBM 1442, that can read up to 400 cards per minute (cpm) and can punch up to 355 cpm. * A line buffer that stores data received or to be transmitted over the communications line. * A binary synchronous adapter which controls the flow of dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 2703
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 adapte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 2701
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] |
Punched Card
A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to directly control automated machinery. Punched cards were widely used through much of the 20th century in the data processing industry, where specialized and increasingly complex unit record machines, organized into semiautomatic data processing systems, used punched cards for data input, output, and storage. The IBM 12-row/80-column punched card format came to dominate the industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and data. While punched cards are now obsolete as a storage medium, as of 2012, some voting machines still used punched cards to record votes. They also had a significant cultural impact. History The idea of control and data storage via punched hole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
At Sign
The at sign, , is normally read aloud as "at"; it is also commonly called the at symbol, commercial at, or address sign. It is used as an accounting and invoice abbreviation meaning "at a rate of" (e.g. 7 widgets @ £2 per widget = £14), but it is now seen more widely in email addresses and social media platform handles. The absence of a single English word for the symbol has prompted some writers to use the French ''arobase'' or Spanish and Portuguese ''arroba'', or to coin new words such as ''ampersat'' and ''asperand'', or the (visual) onomatopoeia '' strudel'', but none of these have achieved wide use. Although not included on the keyboard of the earliest commercially successful typewriters, it was on at least one 1889 model"The @-symbol, part 2 of 2" , [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Number Sign
The symbol is known variously in English-speaking regions as the number sign, hash, or pound sign. The symbol has historically been used for a wide range of purposes including the designation of an ordinal number and as a ligatured abbreviation for pounds avoirdupois – having been derived from the now-rare . Since 2007, widespread usage of the symbol to introduce metadata tags on social media platforms has led to such tags being known as "hashtags", and from that, the symbol itself is sometimes called a hashtag. The symbol is distinguished from similar symbols by its combination of level horizontal strokes and right-tilting vertical strokes. History It is believed that the symbol traces its origins to the symbol , an abbreviation of the Roman term '' libra pondo'', which translates as "pound weight". This abbreviation was printed with a dedicated ligature type element, with a horizontal line across, so that the lowercase letter would not be mistaken for the numeral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percent Sign
The percent sign (sometimes per cent sign in British English) is the symbol used to indicate a percentage, a number or ratio as a fraction of 100. Related signs include the permille (per thousand) sign and the permyriad (per ten thousand) sign (also known as a basis point), which indicate that a number is divided by one thousand or ten thousand, respectively. Higher proportions use parts-per notation. Correct style Form and spacing English style guides prescribe writing the percent sign following the number without any space between (e.g. 50%). However, the International System of Units and ISO 31-0 standard prescribe a space between the number and percent sign, in line with the general practice of using a non-breaking space between a numerical value and its corresponding unit of measurement. Other languages have other rules for spacing in front of the percent sign: * In Czech and in Slovak, the percent sign is spaced with a non-breaking space if the num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apostrophe
The apostrophe ( or ) is a punctuation mark, and sometimes a diacritical mark, in languages that use the Latin alphabet and some other alphabets. In English, the apostrophe is used for two basic purposes: * The marking of the omission of one or more letters, e.g. the contraction of "do not" to "don't". * The marking of possessive case of nouns (as in "the eagle's feathers", "in one month's time", "at your parents' ome). The word "apostrophe" comes ultimately from Greek (, 'he accent ofturning away or elision'), through Latin and French. For use in computer systems, Unicode has code points for three different forms of apostrophe. Usage in English Historical development The apostrophe was first used by Pietro Bembo in his edition of '' De Aetna'' (1496). It was introduced into English in the 16th century in imitation of French practice. French practice Introduced by Geoffroy Tory (1529), the apostrophe was used in place of a vowel letter to indicate elision ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slash (punctuation)
The slash is the oblique slanting line punctuation mark . Also known as a stroke, a solidus or several other historical or technical names including oblique and virgule. Once used to mark periods and commas, the slash is now used to represent division and fractions, exclusive 'or' and inclusive 'or', and as a date separator. A slash in the reverse direction is known as a backslash. History Slashes may be found in early writing as a variant form of dashes, vertical strokes, etc. The present use of a slash distinguished from such other marks derives from the medieval European virgule ( la, virgula, which was used as a period, scratch comma, and caesura mark. (The first sense was eventually lost to the low dot and the other two developed separately into the comma and caesura mark ) Its use as a comma became especially widespread in France, where it was also used to mark the continuation of a word onto the next line of a page, a sense later taken on by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Punched Card")
