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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] |
Getchar
The C (programming language), C programming language provides many standard library subroutine, functions for computer file, file input/output, input and output. These functions make up the bulk of the C standard library header file, header . The functionality descends from a "portable I/O package" written by Mike Lesk at Bell Labs in the early 1970s, and officially became part of the Unix operating system in Version 7 Unix, Version 7. The I/O functionality of C is fairly low-level by modern standards; C abstracts all file operations into operations on stream (computing), streams of bytes, which may be "input streams" or "output streams". Unlike some earlier programming languages, C has no direct support for random access, random-access data files; to read from a record in the middle of a file, the programmer must create a stream, fseek, seek to the middle of the file, and then read bytes in sequence from the stream. The stream model of file I/O was popularized by Unix, which was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
End-of-transmission Character
In telecommunications, an End-of-Transmission character (EOT) is a transmission (telecommunications), 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 (electricity), standby condition. Its most common use today is to cause a Unix computer terminal, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substitute Character
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] |
ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control characters a total of 128 code points. The set of available punctuation had significant impact on the syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers; for example, the first 128 code points of Unicode are the same as ASCII. ASCII encodes each code-point as a value from 0 to 127 storable as a seven-bit integer. Ninety-five code-points are printable, including digits ''0'' to ''9'', lowercase letters ''a'' to ''z'', uppercase letters ''A'' to ''Z'', and commonly used punctuation symbols. For example, the letter is represented as 105 (decimal). Also, ASCII specifies 33 non-printing control codes which originated with ; most of which are now obsolete. The control cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 7-track
IBM's first magnetic-tape data storage devices, introduced in 1952, use what is now generally known as 7-track tape. The magnetic tape is wide, and there are six data tracks plus one parity track for a total of seven parallel tracks that span the length of the tape. Data is stored as six-bit characters, with each bit of the character and the additional parity bit stored in a different track. These tape drives were mechanically sophisticated floor-standing drives that used vacuum columns to buffer long U-shaped loops of tape. Between active control of powerful reel motors and vacuum control of these U-shaped tape loops, extremely rapid start and stop of the tape at the tape-to-head interface could be achieved. When active, the two tape reels thus fed tape into or pulled tape out of the vacuum columns, intermittently spinning in rapid, unsynchronized bursts resulting in visually striking action. Stock shots of such vacuum-column tape drives in motion were widely used to represe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and software. Computing has scientific, engineering, mathematical, technological, and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology, and software engineering. The term ''computing'' is also synonymous with counting and calculation, calculating. In earlier times, it was used in reference to the action performed by Mechanical computer, mechanical computing machines, and before that, to Computer (occupation), human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TOPS-10
TOPS-10 System (Timesharing / Total Operating System-10) is a discontinued operating system from Digital Equipment Corporation (DEC) for the PDP-10 (or DECsystem-10) mainframe computer family. Launched in 1967, TOPS-10 evolved from the earlier "Monitor" software for the PDP-6 and PDP-10 computers; this was renamed to TOPS-10 in 1970. Overview TOPS-10 supported shared memory and allowed the development of one of the first true multiplayer computer games. The game, called DECWAR, was a text-oriented ''Star Trek''-type game. Users at terminals typed in commands and fought each other in real time. TOPS-10 was also the home of the original Multi User Dungeon, MUD, the forerunner to today's MMORPGs. Another groundbreaking application was called ''FORUM''. This application was perhaps the first so-called '' CB Simulator'' that allowed users to converse with one another in what is now known as a chat room. This application showed the potential of multi-user communication and led t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
9-track Tape
9-track tape is a format for magnetic-tape data storage, introduced with the IBM System/360 in 1964. The wide magnetic tape media and reels have the same size as the earlier IBM 7-track format it replaced, but the new format has eight data tracks and one parity track for a total of nine parallel tracks. Data is stored as 8-bit characters, spanning the full width of the tape (including the parity bit). Various recording methods have been employed during its lifetime as tape speed and data density increased, including PE ( phase encoding), GCR ( group-coded recording), and NRZI ( non-return-to-zero, inverted, sometimes pronounced "nur-zee"). Tapes come in various sizes up to in length. The standard size of a byte was effectively set at eight bits with the S/360 and nine-track tape. For over 30 years the format dominated offline storage and data transfer, but by the end of the 20th century it was obsolete, and the last manufacturer of tapes ceased production in early 2002, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Tape Data Storage
Magnetic-tape data storage is a system for storing digital information on magnetic tape using digital recording. Tape was an important medium for primary data storage in early computers, typically using large open reels of 7-track, later 9-track tape. Modern magnetic tape is most commonly packaged in cartridges and cassettes, such as the widely supported Linear Tape-Open (LTO) and IBM 3592 series. The device that performs the writing or reading of data is called a tape drive. Autoloaders and tape libraries are often used to automate cartridge handling and exchange. Compatibility was important to enable transferring data. Tape data storage is now used more for system backup, data archive and data exchange. The low cost of tape has kept it viable for long-term storage and archive. Open reels Initially, magnetic tape for data storage was wound on reels. This standard for large computer systems persisted through the late 1980s, with steadily increasing capacity d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
86-DOS
86-DOS (known internally as QDOS, for Quick and Dirty Operating System) is a discontinued operating system developed and marketed by Seattle Computer Products (SCP) for its Intel 8086-based computer kit. 86-DOS shared a few of its commands with other operating systems such as OS/8 and CP/M, which made it easy to port programs from the latter. Its application programming interface was very similar to that of CP/M. The system was licensed and then purchased by Microsoft and developed further as MS-DOS and PC DOS. History Origins 86-DOS was created because sales of the Seattle Computer Products 8086 computer kit, demonstrated in June 1979 and shipped in November, were languishing due to the absence of an operating system. The only software that SCP could sell with the board was Microsoft's Standalone Disk BASIC-86, which Microsoft had developed on a prototype of SCP's hardware. SCP wanted to offer the 8086-version of CP/M that Digital Research had initially announced fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FAT12
File Allocation Table (FAT) is a file system developed for personal computers and was the default file system for the MS-DOS and Windows 9x operating systems. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. The increase in disk drive capacity over time drove modifications to the design that resulted in versions: FAT12, FAT16, FAT32, and exFAT. FAT was replaced with NTFS as the default file system on Microsoft operating systems starting with Windows XP. Nevertheless, FAT continues to be commonly used on relatively small capacity solid-state storage technologies such as SD card, MultiMediaCard (MMC) and eMMC because of its compatibility and ease of implementation. Uses Historical FAT was used on hard disks throughout the DOS and Windows 9x eras. Microsoft introduced NTFS with the Windows NT platform in 1993, but FAT remained the standard for the home user until the introduction of Windows XP in 2001. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft BASIC
Microsoft BASIC is the foundation software product of the Microsoft company and evolved into a line of BASIC interpreters and compiler(s) adapted for many different microcomputers. It first appeared in 1975 as Altair BASIC, which was the first version of BASIC published by Microsoft as well as the first high-level programming language available for the Altair 8800 microcomputer. During the home computer craze of the late-1970s and early-1980s, Microsoft BASIC was ported to and supplied with many home computer designs. Slight variations to add support for machine-specific functions, especially graphics, led to a profusion of related designs like Commodore BASIC and Atari Microsoft BASIC. As the early home computers gave way to newer designs like the IBM Personal Computer and Macintosh, BASIC was no longer as widely used, although it retained a strong following. The release of Visual Basic rebooted its popularity and it remains in wide use on Microsoft Windows platforms in its m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
