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Ctrl-D
In telecommunications, an End-of-Transmission character (EOT) is a transmission control character. Its intended use is to indicate the conclusion of a transmission that may have included one or more texts and any associated message headings. An EOT is often used to initiate other functions, such as releasing circuits, disconnecting terminals, or placing receive terminals in a standby condition. Its most common use today is to cause a Unix terminal driver to signal end of file and thus exit programs that are awaiting input. In ASCII and Unicode, the character is encoded at . It can be referred to as , in caret notation. Unicode provides the character for when EOT needs to be displayed graphically. In addition, can also be used as a graphic representation of EOT; it is defined in Unicode as "symbol for End of Transmission". Meaning in Unix The EOT character in Unix is different from the Control-Z in DOS. The DOS Control-Z byte is actually sent and/or placed in files to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Character
In computing and telecommunications, a control character or non-printing character (NPC) is a code point in a character encoding, character set that does not represent a written Character (computing), character or symbol. They are used as in-band signaling to cause effects other than the addition of a symbol to the text. All other characters are mainly ''graphic characters'', also known as ''printing characters'' (or ''printable characters''), except perhaps for "space (punctuation), space" characters. In the ASCII standard there are 33 control characters, such as code 7, , which rings a terminal bell. History Prosigns for Morse code, Procedural signs in Morse code are a form of control character. A form of control characters were introduced in the 1870 Baudot code: NUL and DEL. The 1901 Murray code added the carriage return (CR) and line feed (LF), and other versions of the Baudot code included other control characters. The bell character (BEL), which rang a bell to alert op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent Session (computer science), communication sessions. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the electrical telegraph, telegraph, telephone, television, and radio. Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi, who won the 1909 Nobel Prize in Physics. Othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
End-of-file
In computing, end-of-file (EOF) is a condition in a computer operating system where no more data can be read from a data source. The data source is usually called a file or stream. Details In the C standard library, the character-reading functions such as getchar return a value equal to the symbolic value (macro) EOF to indicate that an end-of-file condition has occurred. The actual value of EOF is implementation-dependent and must be negative (it is commonly −1, such as in glibc). Block-reading functions return the number of bytes read, and if this is fewer than asked for, then the end of file was reached or an error occurred (checking of errno or dedicated function, such as ferror is required to determine which). EOF character Input from a terminal never really "ends" (unless the device is disconnected), but it is useful to enter more than one "file" into a terminal, so a key sequence is reserved to indicate end of input. In UNIX, the translation of the keystroke to EOF is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C0 And C1 Control Codes
The C0 and C1 control code or control character sets define control codes for use in text by computer systems that use ASCII and derivatives of ASCII. The codes represent additional information about the text, such as the position of a cursor, an instruction to start a new line, or a message that the text has been received. C0 codes are the range 00 HEX–1FHEX and the default C0 set was originally defined in ISO 646 (ASCII). C1 codes are the range 80HEX–9FHEX and the default C1 set was originally defined in ECMA-48 (harmonized later with ISO 6429). The ISO/IEC 2022 system of specifying control and graphic characters allows other C0 and C1 sets to be available for specialized applications, but they are rarely used. C0 controls ASCII defines 32 control characters, plus the DEL character. This large number of codes was desirable at the time, as multi-byte controls would require implementation of a state machine in the terminal, which was very difficult with contemporary electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 3270
The IBM 3270 is a family of Block-oriented terminal, block oriented display and printer computer terminals introduced by IBM in 1971 and normally used to communicate with IBM mainframes. The 3270 was the successor to the IBM 2260 display terminal. Due to the text color on the original models, these terminals are informally known as ''Monochrome monitor, green screen'' terminals. Unlike a character-oriented terminal, the 3270 minimizes the number of input/output, I/O interrupts required by transferring large blocks of data known as data streams, and uses a high speed proprietary communications interface, using coaxial cable. IBM no longer manufactures 3270 terminals, but the IBM 3270 protocol is still commonly used via TN3270 clients, 3270 emulator, 3270 terminal emulation or web interfaces to access mainframe-based applications, which are sometimes referred to as ''green screen applications''. Principles The 3270 series was designed to connect with mainframe computers, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BUNCH
The BUNCH was the nickname for the group of mainframe computer competitors of IBM in the 1970s. The name is derived from the names of the five companies: Burroughs, UNIVAC, NCR, Control Data Corporation (CDC), and Honeywell. These companies were grouped together because the market share of IBM was much higher than all of its competitors put together. During the 1960s, IBM and these five computer manufacturers, along with RCA and General Electric, had been known as "IBM and the Seven Dwarfs". The description of IBM's competitors changed after GE's 1970 sale of its computer business to Honeywell and RCA's 1971 sale of its computer business to Sperry (who owned UNIVAC), leaving only five "dwarves". The companies' initials thus lent themselves to a new acronym, BUNCH. International Data Corporation estimated in 1984 that BUNCH would receive less than $2 billion of an estimated $11.4 billion in mainframe computer sales that year, with IBM receiving most of the remainder. IBM so domi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burroughs Corporation
The Burroughs Corporation was a major American manufacturer of business equipment. The company was founded in 1886 as the American Arithmometer Company by William Seward Burroughs I, William Seward Burroughs. The company's history paralleled many of the major developments in history of computing, computing. At its start, it produced mechanical adding machines, and later moved into programmable ledgers and then computers. It was one of the largest producers of mainframe computers in the world, also producing related equipment including typewriters and Printer (computing), printers. In the 1960s, the company introduced a range of mainframe computers that were well regarded for their performance running high level languages. These formed the core of the company's business into the 1970s. At that time the emergence of superminicomputers and the dominance of the IBM System/360 and 370 at the high end led to shrinking markets, and in 1986 the company purchased former competitor Sperry C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainframe Computer
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing. A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers, server (computing), servers, workstations, and personal computers. Most large-scale computer-system architectures were established in the 1960s, but they continue to evolve. Mainframe computers are often used as servers. The term ''mainframe'' was derived from the large cabinet, called a ''main frame'', that housed the central processing unit and main computer memory, memory of early computers. Later, the term ''mainframe'' was used to distinguish high-end commercial computers from less powerful machines. Design Modern mainfr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, packaged as a Linux distribution (distro), which includes the kernel and supporting system software and library (computing), libraries—most of which are provided by third parties—to create a complete operating system, designed as a clone of Unix and released under the copyleft GPL license. List of Linux distributions, Thousands of Linux distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian, Fedora Linux, Linux Mint, Arch Linux, and Ubuntu, while commercial distributions include Red Hat Enterprise Linux, SUSE Linux Enterprise, and ChromeOS. Linux distributions are frequently used in server platforms. Many Linux distributions use the word "Linux" in their name, but the Free ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cat (Unix)
cat is a shell command for writing the content of a file or input stream to standard output. The name is an abbreviation of ''concatenate'' which is from the Latin ''catenare'' meaning "to chain" Originally developed for Unix, it is available on many operating systems and shells today. In addition to combining files, cat is commonly used to copy files and in particular to copy a file to the terminal monitor. Unless re-directed, outputs file content on-screen. History cat was part of the early versions of Unix, e.g., Version 1. It replaced pr, a PDP-7 and Multics command for copying a single file to the screen. It was written by Ken Thompson and Dennis Ritchie. The implementation of cat bundled in GNU coreutils was written by Torbjorn Granlund and Richard Stallman. The ReactOS implementation was written by David Welch, Semyon Novikov, and Hermès Bélusca. Over time, alternative utilities such as tac and bat also became available, bringing different new features. Use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control-Z
In computer data, a substitute character (␚) is a control character that is used to pad transmitted data in order to send it in blocks of fixed size, or to stand in place of a character that is recognized to be invalid, erroneous or unrepresentable on a given device. It is also used as an escape sequence in some programming languages. In the ASCII character set, this character is encoded by the number 26 ( hex). Standard keyboards transmit this code when the and keys are pressed simultaneously (, often documented by convention as '')''. Unicode inherits this character from ASCII, but recommends that the replacement character (�, U+FFFD) be used instead to represent un-decodable inputs, when the output encoding is compatible with it. Uses End of file Historically, under PDP-6 monitor, RT-11, VMS, and TOPS-10, and in early PC CP/M 1 and 2 operating systems (and derivatives like MP/M) it was necessary to explicitly mark the end of a file (EOF) because the native file ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
