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Six-bit Character Code
A six-bit character code is a character encoding designed for use on computers with word lengths a multiple of 6. Six bits can only encode 64 distinct characters, so these codes generally include only the upper-case letters, the numerals, some punctuation characters, and sometimes control characters. The 7-track magnetic tape format was developed to store data in such codes, along with an additional parity bit. Types of six-bit codes An early six-bit binary code was used for Braille, the reading system for the blind that was developed in the 1820s. The earliest computers dealt with numeric data only, and made no provision for character data. Six-bit BCD, with several variants, was used by IBM on early computers such as the IBM 702 in 1953 and the IBM 704 in 1954. Six-bit encodings were replaced by the 8-bit EBCDIC code starting in 1964, when System/360 standardized on 8-bit bytes. There are some variants of this type of code (see below). Six-bit character codes generally succee ... [...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] |
BCD (6-bit)
BCD (''binary-coded decimal''), also called alphanumeric BCD, alphameric BCD, BCD Interchange Code, or BCDIC, is a family of representations of numerals, uppercase Latin letters, and some special and control characters as six-bit character codes. Unlike later encodings such as ASCII, BCD codes were not standardized. Different computer manufacturers, and even different product lines from the same manufacturer, often had their own variants, and sometimes included unique characters. Other six-bit encodings with completely different mappings, such as some FIELDATA variants or Transcode, are sometimes incorrectly termed BCD. Many variants of BCD encode the characters '0' through '9' as the corresponding binary values. History Technically, '' binary-coded decimal'' describes the encoding of decimal numbers where each decimal digit is represented by a fixed number of bits, usually four. With the introduction of the ''IBM card'' in 1928, IBM created a code capable of representing a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-10
Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, especially as the TOPS-10 operating system became widely used. The PDP-10's architecture is almost identical to that of DEC's earlier PDP-6, sharing the same 36-bit word length and slightly extending the instruction set (but with improved hardware implementation). Some aspects of the instruction set are unusual, most notably the ''byte'' instructions, which operate on bit fields of any size from 1 to 36 bits inclusive, according to the general definition of a byte as ''a contiguous sequence of a fixed number of bits''. The PDP-10 was found in many university computing facilities and research labs during the 1970s, the most notable being Harvard University's Aiken Computation Laboratory, MIT's AI Lab and Project MAC, Stanford's SAIL, Computer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
36-bit
36-bit computers were popular in the early mainframe computer era from the 1950s through the early 1970s. Starting in the 1960s, but especially the 1970s, the introduction of 7-bit ASCII and 8-bit EBCDIC led to the move to machines using 8-bit bytes, with word sizes that were multiples of 8, notably the 32-bit IBM System/360 mainframe and Digital Equipment VAX and Data General MV series superminicomputers. By the mid-1970s the conversion was largely complete, and microprocessors quickly moved from 8-bit to 16-bit to 32-bit over a period of a decade. The number of 36-bit machines rapidly fell during this period, offered largely for backward compatibility purposes running legacy programs. History Prior to the introduction of computers, the state of the art in precision scientific and engineering calculation was the ten-digit, electrically powered, mechanical calculator, such as those manufactured by Friden, Marchant and Monroe. These calculators had a column of keys for ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identifier
An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, physical countable object (or class thereof), or physical noncountable substance (or class thereof). The abbreviation ID often refers to identity, identification (the process of identifying), or an identifier (that is, an instance of identification). An identifier may be a word, number, letter, symbol, or any combination of those. The words, numbers, letters, or symbols may follow an encoding system (wherein letters, digits, words, or symbols ''stand for'' epresentideas or longer names) or they may simply be arbitrary. When an identifier follows an encoding system, it is often referred to as a code or ID code. For instance the ISO/IEC 11179 metadata registry standard defines a code as ''system of valid symbols that substitute for longer values'' in contrast to identifiers without symbolic meaning. Ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assembly Language
In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per machine instruction (1:1), but constants, comments, assembler directives, symbolic labels of, e.g., memory locations, registers, and macros are generally also supported. The first assembly code in which a language is used to represent machine code instructions is found in Kathleen and Andrew Donald Booth's 1947 work, ''Coding for A.R.C.''. Assembly code is converted into executable machine code by a utility program referred to as an ''assembler''. The term "assembler" is generally attributed to Wilkes, Wheeler and Gill in their 1951 book ''The Preparation of Programs for an Electronic Digital Com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filename
A filename or file name is a name used to uniquely identify a computer file in a directory structure. Different file systems impose different restrictions on filename lengths. A filename may (depending on the file system) include: * name – base name of the file * extension (format or extension) – indicates the content of the file (e.g. .txt, .exe, .html, .COM, .c~ etc.) The components required to identify a file by utilities and applications varies across operating systems, as does the syntax and format for a valid filename. Filenames may contain any arbitrary bytes the user chooses. This may include things like a revision or generation number of the file such as computer code, a numerical sequence number (widely used by digital cameras through the ''DCF'' standard), a date and time (widely used by smartphone camera software and for screenshots), and/or a comment such as the name of a subject or a location or any other text to facilitate the searching the files. In f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until forced to resign in 1992, after the company had gone into precipitous decline. The company produced many different product lines over its history. It is best known for the work in the minicomputer market starting in the mid-1960s. The company produced a series of machines known as the PDP line, with the PDP-8 and PDP-11 being among the most successful minis in history. Their success was only surpassed by another DEC product, the late-1970s VAX "supermini" systems that were designed to replace the PDP-11. Although a number of competitors had successfully competed with Digital through the 1970s, the VAX cemented the company's place as a leading vendor in the computer space. As microcomputers improved in the late 1980s, especially wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO/IEC 7811
ISO/IEC 7811 ''Identification cards — Recording technique'' is a set of nine (7811-1 to 7811-9) standards describing the recording technique on identification cards. It comprises: "Part 1" '' Embossing'' "Part 2" ''Magnetic stripe — Low coercivity Coercivity, also called the magnetic coercivity, coercive field or coercive force, is a measure of the ability of a ferromagnetic material to withstand an external magnetic field without becoming demagnetized. Coercivity is usually measured in ...'' "Part 3" ''Location of embossed characters on ID-1 cards''Part 3 is already withdrawn and revised by Part 1. "Part 4" ''Location of read-only magnetic tracks — Tracks 1 and 2''Part 4 is already withdrawn and revised by Part 2. ''Location of read-write magnetic track — Track 3''Part 5 is already withdrawn and revised by Part 2. ''Magnetic stripe — High coercivity'' ''Magnetic stripe — High coercivity, high density''Allows capacity 10 times that of a card conforming to Par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Stripe Card
The term digital card can refer to a physical item, such as a memory card on a camera, or, increasingly since 2017, to the digital content hosted as a virtual card or cloud card, as a digital virtual representation of a physical card. They share a common purpose: Identity Management, Credit card, or Debit card. A non-physical digital card, unlike a Magnetic stripe card can can emulate (imitate) any kind of card. Other common uses include loyalty card and health insurance card; physical driver's license and Social Security card are still mandated by some government agencies. A smartphone or smartwatch can store content from the card issuer; discount offers and news updates can be transmitted wirelessly, via Internet These virtual cards are used in very high volumes by the mass transit sector, replacing paper based tickets and earlier MagStrip cards. History Magnetic recording on steel tape and wire was invented by Valdemar Poulsen in Denmark around 1900 for recording au ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 700/7000 Series
The IBM 700/7000 series is a series of large-scale (Mainframe computer, mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum-tube logic and were made obsolete by the introduction of the transistor computer, transistorized 7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward. Architectures The IBM 700/7000 series has six completely different ways of storing data and instructions: *First scientific (36/18-bit words): IBM 701, 701 (Defense Calculator) *Later scientific (36-bit words, hardware floating-point): IBM 704, 704, IBM 709, 709, IBM 7040, 7040, IBM 7044, 7044, IBM 7090, 7090, I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 1400 Series
The IBM 1400 series were second-generation (transistor) mid-range business decimal computers that IBM marketed in the early 1960s. The computers were offered to replace tabulating machines like the IBM 407. The 1400-series machines stored information in magnetic cores as variable-length character strings separated on the left by a special bit, called a "wordmark," and on the right by a "record mark." Arithmetic was performed digit-by-digit. Input and output support included punched card, magnetic tape, and high-speed line printers. Disk storage was also available. Many members of the series could be used as independent systems, as extensions to IBM punched-card equipment, or as auxiliary equipment to other computer systems. Some, however, were intended for specific applications or were economical only as independent systems. History The 1401, announced on October 5, 1959, was the first member of the IBM 1400 series. It was the first computer to deploy over 10,000 units. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
