A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
adv. Short for face-to-face. In person, rather than over the Internet. The term is used in e-mail.
n. Time spent dealing face-to-face with another person, rather than communicating electronically.
n. A computer system designed to continue operating without loss of or damage to programs and data when part of the system breaks down or seriously malfunctions. Compare fail-soft system.
n. The inability of a computer system or related device to operate reliably or to operate at all. A common cause of system failure is loss of power, which can be minimized with a battery-powered backup source until all devices can be shut down. Within a system, electronic failures generally occur early in the life of a system or component and can often be produced by burning in the equipment (leaving it turned on constantly) for a few hours or days. Mechanical failures are difficult to predict but are most likely to affect devices, such as disk drives, that have moving parts.
n. The number of failures in a specified time period. Failure rate is a means of measuring the reliability of a device, such as a hard disk. See also MTBF.
n. A series of hardware or software products that have some properties in common, such as a series of personal computers from the same company, a series of CPU chips from the same manufacturer that all use the same instruction set, or a set of fonts that are intended to be used together, such as Times New Roman. See also central processing unit, font, instruction set.
n. The cooling mechanism built into computer cabinets, laser printers, and other such devices to prevent malfunction due to heat buildup. Fans are the main source of the continuous humming associated with computers and other hardware.
vb. To flip through a stack of printer paper to ensure that the pages are loose and will not stick together or jam the printer.
n. Paper with pin-feed holes on both margins designed to be fed into the tractor-feed mechanism of a printer, page by page, in a continuous, unbroken stream. Also called z-fold paper.
n. A magazine, distributed online or by mail, that is produced by and devoted to fans of a particular group, person, or activity. See also ezine.
n. Acronym for frequently asked questions. A document listing common questions and answers on a particular subject. FAQs are often posted on Internet newsgroups where new participants ask the same questions that regular readers have answered many times.
n. Abbreviated F. The unit of capacitance (the ability to hold a charge). A 1-farad capacitor holds a charge of 1 coulomb with a potential difference of 1 volt between its plates. In practical use, a farad is an extremely large amount of capacitance; capacitance is usually expressed in terms of microfarads (10-6) or picofarads (10-12).
n. Ethernet capable of supporting 100 megabits per second. See also Ethernet (definition 1).
n. A form of the SCSI-2 interface that can transfer data 8 bits at a time at up to 10 megabytes per second. The Fast SCSI connector has 50 pins. Also called Fast SCSI-2. See also SCSI, SCSI-2. Compare Fast/Wide SCSI, Wide SCSI.
n. A form of the SCSI-2 interface that can transfer data 16 bits at a time at up to 20 megabytes per second. The Fast/Wide SCSI connector has 68 pins. Also called Fast/Wide SCSI-2. See also SCSI, SCSI-2. Compare Fast SCSI, Wide SCSI.
n. See file allocation table.
n. An error that causes the system or application program to crash--that is, to fail abruptly with no hope of recovery.
n. In a client/server architecture, a client machine that performs most or all of the processing, with little or none performed by the server. The client handles presentation and functions, and the server manages data and access to it. See also client (definition 3), client/server architecture, server (definition 2), thin server. Compare fat server, thin client.
n. The system used by MS-DOS to organize and manage files. The FAT (file allocation table) is a data structure that MS-DOS creates on the disk when the disk is formatted. When MS-DOS stores a file on a formatted disk, the operating system places information about the stored file in the FAT so that MS-DOS can retrieve the file later when requested. The FAT is the only file system MS-DOS can use; OS/2, Windows NT, and Windows 95 operating systems can use the FAT file system in addition to their own file systems (HPFS, NTFS, and VFAT, respectively). See also file allocation table, HPFS, NTFS, OS/2, VFAT, Windows 95, Windows NT.
n. A physical defect, such as a loose connection, that prevents a system or device from operating as it should.
n. The ability of a computer or an operating system to respond to a catastrophic event or fault, such as a power outage or a hardware failure, in a way that ensures that no data is lost and any work in progress is not corrupted. This can be accomplished with a battery-backed power supply, backup hardware, provisions in the operating system, or any combination of these. In a fault-tolerant network, the system has the ability either to continue the system's operation without loss of data or to shut the system down and restart it, recovering all processing that was in progress when the fault occurred.
n. In Microsoft Internet Explorer, a user-defined shortcut to a page on the World Wide Web, analogous to a bookmark in Netscape Navigator. See also Favorites folder, hotlist. Compare bookmark (definition 2).
n. In Microsoft Internet Explorer, a collection of shortcuts to Web sites that a user has selected for future reference. Other Web browsers refer to this collection by other names, such as bookmarks or hotlists. See also bookmark file (definition 1), Internet Explorer, URL. Compare bookmark (definition 2), hotlist.
n. Short for facsimile. The transmission of text or graphics over telephone lines in digitized form. Conventional fax machines scan an original document, transmit an image of the document as a bit map, and reproduce the received image on a printer. Resolution and encoding are standardized in the CCITT Groups 1-4 recommendations. Fax images can also be sent and received by microcomputers equipped with fax hardware and software. See also CCITT Groups 1-4.
n. Short for facsimile machine. A device that scans pages, converts the images of those pages to a digital format consistent with the international facsimile standard, and transmits the image through a telephone line. A fax machine also receives such images and prints them on paper. See also scan (definition 2).
n. A modem that sends (and possibly receives) data encoded in a fax format (typically CCITT fax format), which a fax machine or another modem decodes and converts to an image. The image must already have been encoded on the host computer. Text and graphic documents can be converted into fax format by special software usually provided with the modem; paper documents must first be scanned in. Fax modems may be internal or external and may combine fax and conventional modem capabilities. See also fax, modem.
n. An automated system that makes information available for request by telephone. When a request is made, the system faxes the information to the telephone number given in the request. Acronym: FOD.
n. A computer application that allows the user to send, receive, and print fax transmissions. See also fax.
n. A computer on a network capable of sending and receiving fax transmissions to and from other computers on the network. See also fax, server (definition 1).
n. Acronym for Federal Communications Commission. The U.S. agency created by the Communications Act of 1934, which regulates interstate and international wire, radio, and other broadcast transmissions, including telephone, telegraph, and telecommunications.
n. A coaxial connector, used primarily in video applications, that requires a screw-on attachment.
n. Acronym for Fiber Distributed Data Interface. A standard developed by the American National Standards Institute (ANSI) for high-speed fiber-optic local area networks. FDDI provides specifications for transmission rates of 100 megabits (100 million bits) per second on networks based on the token ring standard. FDDI II, an extension of the FDDI standard, contains additional specifications for the real-time transmission of analog data in digitized form. See also token ring network.
n. Acronym for Full Duplex Handshaking Protocol. A protocol used by duplex modems to determine the source type of the transmission and match it. See also duplex1, handshake.
n. Acronym for frequency-division multiplexing. A means of loading multiple transmission signals onto separate bands of a single communications channel so that all signals can be carried simultaneously. FDM is used in analog transmissions, as on a baseband network or in communications over a telephone line. In FDM the frequency range of the channel is divided into narrower bands, each of which can carry a different transmission signal. For example, FDM might divide a voice channel with a frequency range of 1400 hertz (Hz) into four subchannels--820-990 Hz, 1230-1400 Hz, 1640-1810 Hz, and 2050-2220 Hz--with adjacent subchannels separated by a 240-Hz guard band to minimize interference.
n. An evaluation of a prospective project for the purpose of determining whether or not the project should be undertaken. Feasibility studies normally consider the time, budget, and technology required for completion and are generally used in computing departments in large organizations.
n. A unique, attractive, or desirable property of a program or of a computer or other hardware.
n. A system of standards, guidelines, and technical methods for information processing within the U.S. federal government. Acronym: FIPS.
vb. 1. To advance paper through a printer. 2. To supply media to a recording device, as by inserting disks into a disk drive.
n. The return of a portion of system output as input to the same system. Often feedback is deliberately designed into a system, but sometimes it is unwanted. In electronics, feedback is used in monitoring, controlling, and amplifying circuitry.
n. A connector that has one or more receptacles for the insertion of pins. Female connector part numbers often include an F (female), an S (socket), a J (jack), or an R (receptacle). For example, a female DB-25 connector might be labeled DB-25S or DB-25F. (Note that although the letter F can denote a female connector, it does not have that meaning in F connector, which is a type of coaxial cable connector.) Compare male connector.
n. A technology for the transmission of light beams along optical fibers. A light beam, such as that produced in a laser, can be modulated to carry information. Because light has a higher frequency on the electromagnetic spectrum than other types of radiation, such as radio waves, a single fiber-optic channel can carry significantly more information than most other means of information transmission. Optical fibers are thin strands of glass or other transparent material, with dozens or hundreds of strands housed in a single cable. Optical fibers are essentially immune to electromagnetic interference. See also optical fiber.
n. 1. A location in a record in which a particular type of data is stored. For example, EMPLOYEE-RECORD might contain fields to store Last-Name, First-Name, Address, City, State, Zip-Code, Hire-Date, Current-Salary, Title, Department, and so on. Individual fields are characterized by their maximum length and the type of data (for example, alphabetic, numeric, or financial) that can be placed in them. The facility for creating these specifications usually is contained in the data definition language (DDL). In relational database management systems, fields are called columns. 2. A space in an on-screen form where the user can enter a specific item of information.
n. A complete, named collection of information, such as a program, a set of data used by a program, or a user-created document. A file is the basic unit of storage that enables a computer to distinguish one set of information from another. A file is the "glue" that binds a conglomeration of instructions, numbers, words, or images into a coherent unit that a user can retrieve, change, delete, save, or send to an output device.
n. A table or list maintained by some operating systems to manage disk space used for file storage. Files on a disk are stored, as space allows, in fixed-size groups of bytes (characters) rather than from beginning to end as contiguous strings of text or numbers. A single file can thus be scattered in pieces over many separate storage areas. A file allocation table maps available disk storage space so that it can mark flawed segments that should not be used and can find and link the pieces of a file. In MS-DOS, the file allocation table is commonly known as the FAT. See also FAT file system.
n. A restrictive label attached to a file that describes and regulates its use--for example, hidden, system, read-only, archive, and so forth. In MS-DOS, this information is stored as part of the file's directory entry.
n. The process of transforming the data in a file from one format to another without altering its contents--for example, converting a file from a word processor's format to its ASCII equivalent.
n. The structure of a file that defines the way it is stored and laid out on the screen or in print. The format can be fairly simple and common, as are files stored as "plain" ASCII text, or it can be quite complex and include various types of control instructions and codes used by programs, printers, and other devices. Examples include RTF (Rich Text Format), DCA (Document Content Architecture), PICT, DIF (Data Interchange Format), DXF, TIFF (Tagged Image File Format), and EPSF (Encapsulated PostScript Format).
n. 1. The breaking apart of files into small, separate segments for storage on disk. The condition is a natural consequence of enlarging files and saving them on a crowded disk that no longer contains contiguous blocks of free space large enough to hold them. File fragmentation is not an integrity problem, although it can eventually slow read and write access times if the disk is very full and storage is badly fragmented. Software products are available for redistributing (optimizing) file storage to reduce fragmentation. 2. In a database, a situation in which records are not stored in their optimal access sequence because of accumulated additions and deletions of records. Most database systems offer or contain utility programs that resequence records to improve efficiency of access and to aggregate free space occupied by deleted records.
n. In MS-DOS, OS/2, and Windows, a token (number) that the system uses to identify or refer to an open file or, sometimes, to a device.
n. Broadly, the process of changing information in a file, altering a file's control information or structure, or copying and archiving files. A person using a terminal to enter data, the program accepting the data from the terminal and writing it to a data file, and a database administrator using a utility to alter the format of a database file are all forms of file maintenance.
n. A module of an operating system or environment that controls the physical placement of and access to a group of program files.
n. The process of reconstructing lost or unreadable files on disk. Files are lost when they are inadvertently deleted, when on-disk information about their storage is damaged, or when the disk is damaged. File recovery involves the use of utility programs that attempt to rebuild on-disk information about the storage locations of deleted files. Because deletion makes the file's disk space available but does not remove the data, data that has not yet been overwritten can be recovered. In the case of damaged files or disks, recovery programs read whatever raw data they can find, and save the data to a new disk or file in ASCII or numeric (binary or hexadecimal) form. In some instances, however, such reconstructed files contain so much extraneous or mixed information that they are unreadable. The best way to recover a file is to restore it from a backup copy.
n. The act of transferring a data file from a storage location to the machine where it is to be used.
n. A file-storage device on a local area network that is accessible to all users on the network. Unlike a disk server, which appears to the user as a remote disk drive, a file server is a sophisticated device that not only stores files but manages them and maintains order as network users request files and make changes to them. To deal with the tasks of handling multiple--sometimes simultaneous--requests for files, a file server contains a processor and controlling software as well as a disk drive for storage. On local area networks, a file server is often a computer with a large hard disk that is dedicated only to the task of managing shared files. Compare disk server.
n. The use of computer files on networks, wherein files are stored on a central computer or a server and are requested, reviewed, and modified by more than one individual. When a file is used with different programs or different computers, file sharing can require conversion to a mutually acceptable format. When a single file is shared by many people, access can be regulated through such means as password protection, security clearances, or file locking to prohibit changes to a file by more than one person at a time.
n. The length of a file, typically given in bytes. A computer file stored on disk actually has two file sizes, logical size and physical size. The logical file size corresponds to the file's actual size--the number of bytes it contains. The physical size refers to the amount of storage space allotted to the file on disk. Because space is set aside for a file in blocks of bytes, the last characters in the file might not completely fill the block (allocation unit) reserved for them. When this happens, the physical size is larger than the logical size of the file.
n. A description of a file or group of files that are to be treated together for some purpose. Such a description includes file layout and location for each file under consideration.
n. In an operating system, the overall structure in which files are named, stored, and organized. A file system consists of files, directories, and the information needed to locate and access these items. The term can also refer to the portion of an operating system that translates requests for file operations from an application program into low-level, sector-oriented tasks that can be understood by the drivers controlling the disk drives. See also driver.
n. The process of moving or transmitting a file from one location to another, as between two programs or over a network.
n. See FTP1 (definition 1).
n. A designation of the operational or structural characteristics of a file. A file's type is often identified in the filename. With MS-DOS, a file's type is usually reflected in the filename extension. See also file format.
n. In computer graphics, to "paint" the inside of an enclosed figure, such as a circle, with color or a pattern. The portion of the shape that can be colored or patterned is the fill area. Drawing programs commonly offer tools for creating filled or nonfilled shapes; the user can specify color or pattern.
n. 1. A program or set of features within a program that reads its standard or designated input, transforms the input in some desired way, and then writes the output to its standard or designated output destination. A database filter, for example, might flag information of a certain age. 2. In communications and electronics, hardware or software that selectively passes certain elements of a signal and eliminates or minimizes others. A filter on a communications network, for example, must be designed to transmit a certain frequency but attenuate (dampen) frequencies above it (a lowpass filter), those below it (a highpass filter), or those above and below it (a bandpass filter). 3. A pattern or mask through which data is passed to weed out specified items. For instance, a filter used in e-mail or in retrieving newsgroup messages can allow users to filter out messages from other users. See also e-mail filter, mask. 4. In computer graphics, a special effect or production effect that is applied to bitmapped images; for example, shifting pixels within an image, making elements of the image transparent, or distorting the image. Some filters are built into a graphics program, such as a paint program or an image editor. Others are separate software packages that plug into the graphics program. See also bitmapped graphics, image editor, paint program.
n. A Windows 95 accessibility control panel feature that enables users with physical disabilities to use the keyboard. With FilterKeys, the system ignores brief and repeated keystrokes that result from slow or inaccurate finger movements. See also accessibility. Compare MouseKeys, ShowSounds, SoundSentry, StickyKeys, ToggleKeys.
n. The standard interface to the Macintosh operating system, allowing the user to view the contents of directories (folders); to move, copy, and delete files; and to launch applications. Items in the system are often represented as icons, and a mouse or similar pointing device is used to manipulate these items. The Finder was the first commercially successful graphical user interface, and it helped launch a wave of interest in icon-based systems. See also MultiFinder.
n. An Internet utility, originally limited to UNIX but now available on many other platforms, that enables a user to obtain information on other users who may be at other sites (if those sites permit access by finger). Given an e-mail address, finger returns the user's full name, an indication of whether or not the user is currently logged on, and any other information the user has chosen to supply as a profile. Given a first or last name, finger returns the logon names of users whose first or last names match.
vb. To obtain information on a user by means of the finger program.
n. A security system intended to protect an organization's network against external threats, such as hackers, coming from another network, such as the Internet. A firewall prevents computers in the organization's network from communicating directly with computers external to the network and vice versa. Instead, all communication is routed through a proxy server outside of the organization's network, and the proxy server decides whether it is safe to let a particular message or file pass through to the organization's network.
n. Software routines stored in read-only memory (ROM). Unlike random access memory (RAM), read-only memory stays intact even in the absence of electrical power. Startup routines and low-level input/output instructions are stored in firmware. It falls between software and hardware in terms of ease of modification. See also RAM, ROM.
n. Short for fast infrared port. A wireless I/O port, most common on a portable computer, that exchanges data with an external device using infrared light. See also infrared, input/output port.
n. A method of processing a queue, in which items are removed in the same order in which they were added--the first in is the first out. Such an order is typical of a list of documents waiting to be printed. See also queue. Compare last in, first out. Acronym: FIFO.
n. Acronym for Federal Internet Exchange. A connection point between the U.S. government's various internets and the Internet. There are two Federal Internet Exchanges: FIX West, in Mountain View, California; and FIX East, in College Park, Maryland. Together, they link the backbones of MILNET, ESnet (the TCP/IP network of the Department of Energy), and NSInet (NASA Sciences Internet) with NSFnet. See also backbone (definition 1), MILNET, NSFnet, TCP/IP.
n. A set amount of horizontal space used to separate characters in text--often, the width of a numeral in a given font. See also em space, en space, thin space.
n. 1. Broadly, a marker of some type used by a computer in processing or interpreting information; a signal indicating the existence or status of a particular condition. Flags are used in such areas as communications, programming, and information processing. Depending on its use, a flag can be a code, embedded in data, that identifies some condition, or it can be one or more bits set internally by hardware or software to indicate an event of some type, such as an error or the result of comparing two values. 2. In the HDLC communications protocol, a flag is the unique series of bits 01111110, used to start and end a transmission frame (message unit). See also HDLC.
n. An abusive or personally insulting e-mail message or newsgroup posting.
vb. 1. To send an abusive or personally insulting e-mail message or newsgroup posting. 2. To criticize personally by means of e-mail messages or newsgroup postings.
n. A posting to a mailing list, newsgroup, or other online conference that is likely to provoke flames, often because it expresses a controversial opinion on a highly emotional topic. See also flame1, flame war. Compare troll.
n. A series of inflammatory messages or articles in a newsgroup or other online conference.
n. A person who sends or posts abusive messages via e-mail, in newsgroups and other online forums, and in online chats. See also chat1 (definition 1), newsgroup.
n. A discussion in a mailing list, newsgroup, or other online conference that has turned into a protracted exchange of flames. See also flame1.
n. A type of nonvolatile memory. Flash memory is similar to EEPROM memory in function but it must be erased in blocks, whereas EEPROM can be erased one byte at a time. Because of its block-oriented nature, flash memory is commonly used as a supplement to or replacement for hard disks in portable computers. In this context, flash memory either is built into the unit or, more commonly, is available as a PC Card that can be plugged into a PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannot be practically used as main memory (RAM) because a computer needs to be able to write to memory in single-byte increments. See also EEPROM, nonvolatile memory, PC Card, PCMCIA slot.
n. An address space in which each location in memory is specified by a unique number. (Memory addresses start at 0 and increase sequentially by 1.) The Macintosh operating system, OS/2, and Windows NT use a flat address space. MS-DOS uses a segmented address space, in which a location must be accessed with a segment number and an offset number. See also segmentation. Compare segmented address space.
n. A scanner with a flat transparent surface that holds the image to be scanned, generally a book or other paper document. A scan head below the surface moves across the image. Some flatbed scanners can also reproduce transparent media, such as slides. Compare drum scanner, handheld scanner, sheet-fed scanner.
n. A file consisting of records of a single record type in which there is no embedded structure information that governs relationships between records.
n. A database that takes the form of a table, where only one table can be used for each database. A flat-file database can only work with one file at a time. Compare relational database.
n. A directory that cannot contain subdirectories but simply contains a list of filenames. Compare hierarchical file system.
n. Memory that appears to a program as one large addressable space, whether consisting of RAM or virtual memory. The 68000 and VAX processors have flat memory; by contrast, 80x86 processors operating in real mode have segmented memory. Also called linear memory.
n. One of several varieties of a system, having its own details of operation. UNIX in particular is found in distinct flavors, such as BSD UNIX or AT&T UNIX System V.
n. Rapid, visible fluctuation in a screen image, as on a television or computer monitor. Flicker occurs when the image is refreshed (updated) too infrequently or too slowly for the eye to perceive a steady level of brightness. In television and raster-scan displays, flicker is not noticeable when the refresh rate is 50 to 60 times per second. Interlaced displays, in which the odd-numbered scan lines are refreshed on one sweep and even-numbered lines on the other, achieve a flicker-free effective refresh rate of 50 to 60 times per second because the lines appear to merge, even though each line is actually updated only 25 to 30 times per second.
n. A computer-generated recreation of the experience of flying. Sophisticated flight simulators costing hundreds of thousands of dollars can provide pilot training, simulating emergency situations without putting human crews and planes at risk. Flight simulator software running on personal computers simulates flight in a less realistic fashion; it provides entertainment and practice in navigation and instrument reading.
n. Arithmetic performed on floating-point numbers. See also floating-point notation, floating-point number.
n. A numeric format that can be used to represent very large real numbers and very small real numbers. Floating-point numbers are stored in two parts, a mantissa and an exponent. The mantissa specifies the digits in the number, and the exponent specifies the magnitude of the number (the position of the decimal point). For example, the numbers 314,600,000 and 0.0000451 are expressed respectively as 3146E5 and 451E-7 in floating-point notation. Most microprocessors do not directly support floating-point arithmetic; consequently, floating-point calculations are performed either by using software or with a special floating-point processor. Also called exponential notation. See also fixed-point notation, floating-point processor, integer.
n. A coprocessor for performing arithmetic on floating-point numbers. Adding a floating-point processor to a system can speed up the processing of math and graphics dramatically if the software is designed to recognize and use it. The i486DX and 68040 and higher microprocessors have built-in floating-point processors. Also called math coprocessor, numeric coprocessor. See also floating-point notation, floating-point number.
n. A round piece of flexible plastic film coated with ferric oxide particles that can hold a magnetic field. When placed inside a disk drive, the floppy disk rotates to bring different areas, or sectors, of the disk surface under the drive's read/write head, which can detect and alter the orientation of the particles' magnetic fields to represent binary 1s and 0s. A floppy disk 5.25 inches in diameter is encased in a flexible plastic jacket and has a large hole in the center, which fits around a spindle in the disk drive; such a disk can hold from a few hundred thousand to over one million bytes of data. A 3.5-inch disk encased in rigid plastic is also called a floppy disk or a microfloppy disk. In addition, 8-inch floppy disks were common in DEC and other minicomputer systems. See also 3.5-inch floppy disk, 5.25-inch floppy disk, microfloppy disk.
n. An electromechanical device that reads data from and writes data to floppy or microfloppy disks. See also floppy disk.
adj. Using a combination of magnetic and optical technology to achieve a very high data density on special 3.5-inch disks. Data is written to and read from the disk magnetically, but the read/write head is positioned optically by means of a laser and grooves on the disk. The term was coined by and is a registered trademark of Insite Peripherals.
n. A method of tracing the movement of different types of information through a computer system, especially with regard to security and the controls applied to ensure the integrity of the information. See also flowchart.
n. A graphic map of the path of control or data through the operations in a program or an information-handling system. Symbols such as squares, diamonds, and ovals represent various operations. These symbols are connected by lines and arrows to indicate the flow of data or control from one point to another. Flowcharts are used both as aids in showing the way a proposed program will work and as a means of understanding the operations of an existing program.
adj. Aligned in a certain way on the screen or on paper. Flush left, for example, means aligned on the left side; flush right means aligned on the right side. See also align (definition 1).
vb. To clear a portion of memory. For example, to flush a disk file buffer is to save its contents on disk and then clear the buffer for filling again.
vb. In television and raster-scan displays, to make an electron beam converge at a single point on the inner surface of the screen.
n. In the Mac OS, Windows 95, and other operating systems, a container for programs and files in graphical user interfaces, symbolized on the screen by a graphical image (icon) of a file folder. This container is called a directory in other systems, such as MS-DOS and UNIX. A folder is a means of organizing programs and documents on a disk and can hold both files and additional folders. It first appeared commercially in Apple Computer's Lisa in 1983 and in the Apple Macintosh in 1984. See also directory.
n. A post to a newsgroup that replies to an article. The follow-up has the same subject line as the original article, with the prefix "Re:" attached. An article and all of its follow-ups, in the order they were received, constitute a thread, which a user can read together using a newsreader.
n. A set of characters of the same typeface (such as Garamond), style (such as italic), and weight (such as bold). A font consists of all the characters available in a particular style and weight for a particular design; a typeface consists of the design itself. Fonts are used by computers for on-screen displays and by printers for hard-copy output. In both cases, the fonts are stored either as bit maps (patterns of dots) or as outlines (defined by a set of mathematical formulas). Even if the system cannot simulate different typefaces on the screen, application programs may be able to send information about typeface and style to a printer, which can then reproduce the font if a font description is available. See also bit map, font generator.
n. A plug-in unit available for some printers that contains fonts in several different styles and sizes. Font cartridges, like downloadable fonts, enable a printer to produce characters in sizes and styles other than those created by the fonts built into it. Also called font card. See also ROM cartridge.
n. A utility program that enables the user to modify existing fonts or to create and save new ones. Such an application commonly works with a screen representation of the font, with a representation that can be downloaded to a PostScript or other printer, or with both. See also PostScript font, screen font.
n. The set of available fonts representing variations of a single typeface. For example, Times Roman and Times Roman Italic are members of the same font family. When the user indicates "italic," the system selects the correct italic font for the font family, with its characteristic appearance. If there is no italic font in the family, the system simply slants, or "obliques," the corresponding roman character. See also italic, roman.
n. The point size of a set of characters in a particular typeface. See also point1 (definition 1).
n. A file on Macintosh computers that contains one or more fonts or desk accessories. Such files are indicated in early versions of the operating system with the icon of a suitcase marked with a capital A. From System 7.0 onward, this icon is used to denote individual fonts.
n. One or more identifying lines printed at the bottom of a page. A footer may contain a folio (page number), a date, the author's name, and the document title. Also called running foot. Compare header (definition 1).
n. The surface area occupied by a personal computer or other device.
adj. Currently having control of the system and responding to commands issued by the user. See also multitasking. Compare background1.
n. 1. The color of displayed characters and graphics. Compare background2 (definition 1). 2. The condition of the program or document currently in control and affected by commands and data entry in a windowing environment. Compare background2 (definition 4).
n. One of the two parts of a file recognized by the Mac OS. A Macintosh file has a data fork and a resource fork. Most or all of a typical user-produced document is in the data fork; the resource fork usually contains application-oriented information, such as fonts, dialog boxes, and menus. See also data fork, resource fork.
vb. To initiate a child process in a multitasking system after a parent process has been started. See also multitasking.
n. 1. A structured document with spaces reserved for entering information and often containing special coding as well. 2. In some applications (especially databases), a structured window, box, or other self-contained presentation element with predefined areas for entering or changing information. A form is a visual "filter" for the underlying data it is presenting, generally offering the advantages of better data organization and greater ease of viewing. 3. In optical media, a data storage format used in compact disc technology. 4. In programming, a metalanguage (such as Backus-Naur form) used to describe the syntax of a language. See also Backus-Naur form.
n. 1. In general, the structure or appearance of a unit of data. 2. The arrangement of data within a document file that typically permits the document to be read or written by a certain application. Many applications can store a file in a more generic format, such as plain ASCII text. 3. The layout of data storage areas (tracks and sectors) on a disk. 4. The order and types of fields in a database. 5. The attributes of a cell in a spreadsheet, such as its being alphabetic or numeric, the number of digits, the use of commas, and the use of currency signs. 6. The specifications for the placement of text on a page or in a paragraph.
vb. 1. To change the appearance of selected text or the contents of a selected cell in a spreadsheet. 2. To prepare a disk for use by organizing its storage space into a collection of data "compartments," each of which can be located by the operating system so that data can be sorted and retrieved. When a previously used disk is formatted, any preexisting information on it is lost.
n. A toolbar within an application used for modifying the format of the document being displayed, such as changing font size or type.
n. 1. The elements of style and presentation that are added to documents through the use of margins, indents, and different sizes, weights, and styles of type. 2. The process of initializing a disk so that it can be used to store information. See also initialize.
n. A printer command that tells a printer to move to the top of the next page. In the ASCII character set, the form-feed character has the decimal value 12 (hexadecimal 0C). Because its purpose is to begin printing on a new page, form feed is also known as the page-eject character. Acronym: FF.
n. A letter created for printing and distribution to a group of people whose names and addresses are taken from a database and inserted by a mail-merge program into a single basic document. See also mail merge.
or Fortran n. Acronym for formula translation. The first high-level computer language (developed over the period 1954-58 by John Backus) and the progenitor of many key high-level concepts, such as variables, expressions, statements, iterative and conditional statements, separately compiled subroutines, and formatted input/output. FORTRAN is a compiled, structured language. The name indicates its roots in science and engineering, where it is still used heavily, although the language itself has been expanded and improved vastly over the last 35 years to become a language that is useful in any field. See also compiled language, structured programming.
n. A proverb, prediction, joke, or other phrase chosen at random from a collection of such items and output to the screen by a program. Fortune cookies are sometimes displayed at logon and logoff times by UNIX systems.
n. A medium provided by an online service or BBS for users to carry on written discussions of a particular topic by posting messages and replying to them. On the Internet, the most widespread forums are the newsgroups in Usenet.
vb. In e-mail, to send a received message, either modified or in its entirety, to a new recipient.
n. A word coined by mathematician Benoit Mandelbrot in 1975 to describe a class of shapes characterized by irregularity, but in a way that evokes a pattern. Computer graphics technicians often use fractals to generate naturelike images such as landscapes, clouds, and forests. The distinguishing characteristic of fractals is that they are "self-similar"; any piece of a fractal, when magnified, has the same character as the whole. The standard analogy is that of a coastline, which has a similar structure whether viewed on a local or continental scale. Interestingly, it is often difficult to measure the length of the perimeter of such a shape exactly because the total distance measured depends on the size of the smallest element measured. For example, one could measure on a given coastline the perimeter of every peninsula and inlet, or at a higher magnification the perimeter of every small promontory and jetty, and so on. In fact, a given fractal may have a finite area but an infinite perimeter; such shapes are considered to have a fractional dimension--for example, between 1 (a line) and 2 (a plane)--hence the name fractal. See also cellular automata, graftal.
n. A shared connection to a T1 line, in which only a fraction of the 24 T1 voice or data channels are used. See also T1. Acronym: FT1.
n. The scattering of parts of the same disk file over different areas of the disk. Fragmentation occurs as files on a disk are deleted and new files are added. Such fragmentation slows disk access and degrades the overall performance of disk operations, although usually not severely. Utility programs are available for rearranging file storage on fragmented disks.
n. 1. In asynchronous serial communications, a unit of transmission that is sometimes measured in elapsed time and begins with the start bit that precedes a character and ends with the last stop bit that follows the character. 2. In synchronous communications, a package of information transmitted as a single unit. Every frame follows the same basic organization and contains control information, such as synchronizing characters, station address, and an error-checking value, as well as a variable amount of data. For example, a frame used in the widely accepted HDLC and related SDLC protocols begins and ends with a unique flag (01111110). See also HDLC, SDLC. 3. A single screen-sized image that can be displayed in sequence with other, slightly different, images to create animated drawings. 4. The storage required to hold one screen-sized image of text, graphics, or both. 5. A rectangular space containing, and defining the proportions of, a graphic. 6. The part of an on-screen window (title bar and other elements) that is controlled by the operating system rather than by the application running in the window. 7. A rectangular section of the page displayed by a Web browser that is a separate HTML document from the rest of the page. Web pages can have multiple frames, each of which is a separate document. Associated with each frame are the same capabilities as for an unframed Web page, including scrolling and linking to another frame or Web site; these capabilities can be used independently of other frames on the page. Frames, which were introduced in Netscape Navigator 2.0, are often used as a table of contents for one or more HTML documents on a Web site. Most current Web browsers support frames, although older ones do not. See also HTML document, Web browser.
n. 1. The speed at which full, single-screen images are transmitted to and displayed by a raster-scan monitor. Frame rate is calculated as the number of times per second (hertz) the electron beam sweeps the screen. 2. In animation, the number of times per second an image is updated. When the frame rate exceeds about 14 frames per second, animation seems to blend into smooth motion. See also animation.
n. A packet-switching protocol for use on wide area networks. Frame relay transmits variable-length packets at up to 1.544 Mbps. It is a variant of X.25 but dispenses with some of X.25's error detection for the sake of speed. See also ATM (definition 1), X.25.
n. A combination channel service unit/digital service unit (CSU/DSU) and router that connects an internal network to a frame relay connection. The device converts data (which may be in the form of IP packets or conform to some other network protocol) into packets for transmission over the frame relay network and converts such packets back to the original data. Since this type of connection is direct, without a firewall, other network protection is necessary. See also firewall, frame relay, IP. Acronym: FRAD.
n. In the HTML frames environment, a contents document that will look for the source document to display within a frame drawn by the local browser. See also HTML.
n. 1. An interface utility for X.500. See also CCITT X series. 2. A placeholder string used by programmers in syntax examples to stand for a variable name. If a programmer has used fred, the next placeholder needed is likely to be barney. Compare foo.
n. A freely distributed version of BSD UNIX (Berkeley Software Distribution UNIX) for IBM and IBM-compatible PCs. See also BSD UNIX.
or free-net n. A community-based computer BBS and Internet service provider, usually operated by volunteers and providing free access to subscribers in the community or access for a very small fee. Many freenets are operated by public libraries or universities. See also ISP.
n. Software, complete with source code, that is distributed freely to users who are in turn free to use, modify, and distribute it, provided that all alterations are clearly marked and that the name and copyright notice of the original author are not deleted or modified in any way. Unlike freeware, which a user might or might not have permission to modify, free software is protected by a license agreement. Free software is a concept pioneered by the Free Software Foundation in Cambridge, Massachusetts. Compare freeware, public-domain software, shareware.
n. An advocacy organization founded by Richard Stallman, dedicated to eliminating restrictions on people's right to use, copy, modify, and redistribute computer programs for noncommercial purposes. The Free Software Foundation is the maintainer of GNU software, a UNIX system that can be freely distributed. See also GNU.
n. Space on a floppy disk or a hard drive not currently occupied by data. See also floppy disk, hard disk.
n. A computer program given away free of charge and often made available on the Internet or through user groups. An independent program developer might offer a product as freeware either for personal satisfaction or to assess its reception among interested users. Freeware developers often retain all rights to their software, and users are not necessarily free to copy or distribute it further. Compare free software, public-domain software, shareware.
n. The measure of how often a periodic event occurs, such as a signal going through a complete cycle. Frequency is usually measured in hertz (Hz), with 1 Hz equaling 1 occurrence (cycle) per second. In the United States, household electricity is alternating current with a frequency of 60 Hz. Frequency is also measured in kilohertz (kHz, or 1,000 Hz), megahertz (MHz, or 1,000 kHz), gigahertz (GHz, or 1,000 MHz), or terahertz (THz, or 1,000 GHz). Compare wavelength.
n. A way of encoding information in an electrical signal by varying its frequency. The FM radio band uses frequency modulation, as does the audio portion of broadcast television. Compare amplitude modulation. Acronym: FM.
n. Abbreviated FM encoding. A method of storing information on a disk in which both data and additional synchronizing information, called clock pulses, are recorded on the surface. FM encoding is relatively inefficient because of the extra disk space required by the clock pulses. It has been generally superseded by a more efficient method called modified frequency modulation (MFM) encoding and by the complex but extremely efficient technique called run-length limited (RLL) encoding. Compare modified frequency modulation encoding, run-length limited encoding.
adj. Referring to features built into hardware or software that make a computer or computer program easy to learn and easy to use. Friendliness is emphasized by most developers and sought after by most users. See also user-friendly.
n. Freeware whose reliability and value are questionable. See also freeware.
n. In applications, software or a feature of software that provides an interface to another application or tool. Front ends are often used to supply a common interface for a range of tools produced by a software manufacturer. A front end generally offers a more user-friendly interface than that of the application running "behind" it.
n. 1. Generally, a computer or processing unit that produces and manipulates data before another processor receives it. Compare back-end processor (definition 2). 2. In communications, a computer that is located between communications lines and a main (host) computer and is used to relieve the host of housekeeping chores related to communications; sometimes considered synonymous with communications controller. A front-end processor is dedicated entirely to handling transmitted information, including error detection and control; receipt, transmission, and possibly encoding of messages; and management of the lines running to and from other devices. See also communications controller.
n. The faceplate of a computer cabinet through which the control knobs, switches, and lights are available to an operator. See also console.
vb. To destroy a circuit board or another component of a computer by applying excessive voltage. Even when applied voltage is not excessive, an electronic component can become fried when it breaks down, conducting more current than its design permits.
n. 1. Acronym for File Transfer Protocol, the protocol used for copying files to and from remote computer systems on a network using TCP/IP, such as the Internet. This protocol also allows users to use FTP commands to work with files, such as listing files and directories on the remote system. See also TCP/IP. 2. A common logon ID for anonymous FTP.
vb. To download files from or upload files to remote computer systems, via the Internet's File Transfer Protocol. The user needs an FTP client to transfer files to and from the remote system, which must have an FTP server. Generally, the user also needs to establish an account on the remote system to FTP files, although many FTP sites permit the use of anonymous FTP. See also FTP client, FTP server.
or ftp client n. A program that enables the user to upload and download files to and from an FTP site over a network, such as the Internet, using the File Transfer Protocol. See also FTP1 (definition 1). Compare FTP server.
n. Commands that are part of the File Transfer Protocol. See also FTP1 (definition 1).
n. A file server that uses the File Transfer Protocol to permit users to upload or download files through the Internet or any other TCP/IP network. See also file server, FTP1 (definition 1), TCP/IP. Compare FTP client.
n. The collection of files and programs residing on an FTP server. See also FTP1 (definition 1), FTP server. See FTP server.
n. In typesetting, word processing, and desktop publishing, the process of aligning text evenly along both the left and right margins of a column or page. See also justify (definition 2).
n. Digital video that is displayed at 30 frames per second (fps). Compare freeze-frame video.
n. An expansion card for a computer that can convert motion video from devices such as a video cassette recorder to a digital format that a computer can use such as AVI, MPEG, or Motion JPEG. See also AVI, Motion JPEG, MPEG.
n. A pathname containing all the possible components of a pathname, including the drive, root directory, any subdirectories, and the file or object name. See also pathname, root directory, subdirectory. Compare relative path.
n. In a hierarchical filing system, a listing of the directories or folders that lead from the root directory of a disk drive to a particular file. For example, the MS-DOS full pathname c:\book\chapter\myfile.doc indicates that myfile.doc is located in a directory called chapter, which in turn is located in a directory called book in the root directory of the C: drive. See also path (definition 2).
n. A search for one or more documents, records, or strings based on all of the actual text data rather than on an index containing a limited set of keywords. For example, a full-text search can locate a document containing the words "albatrosses are clumsy on land" by searching files for just those words without the need of an index containing the keyword "albatross." See also index.
n. Any of the 10 or more keys labeled F1, F2, F3, and so on, that are placed along the left side or across the top of a keyboard (or both) and are used for special tasks by different programs. The meaning of a function key is defined by a program or, in some instances, by the user. Function keys are used in application programs or the operating system to provide either a shortcut for a series of common instructions (such as calling up a program's on-screen help facility) or a feature that is not otherwise available. See also key (definition 1). Compare Command key, Control key, Escape key.
n. A form of logic used in some expert systems and other artificial-intelligence applications in which variables can have degrees of truthfulness or falsehood represented by a range of values between 1 (true) and 0 (false). With fuzzy logic, the outcome of an operation can be expressed as a probability rather than as a certainty. For example, an outcome might be probably true, possibly true, possibly false, or probably false. See also expert system.
n. 1. Acronym for for your information. An expression used in e-mail and newsgroups to introduce information that is thought to be useful to the reader. 2. An electronic document distributed through InterNIC like a request for comments (RFC), but intended to explain an Internet standard or feature for users rather than to define it for developers, as the RFC does. See also InterNIC. Compare RFC.
