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OAGI n. Acronym for Open Applications Group, Inc. A nonprofit consortium of software vendors and businesses created to develop and define XML-based interoperability specifications and standards among enterprise-scale applications. The OAGI was formed in 1995 by a small number of business enterprise software companies and organizations and has grown to more than sixty member companies.
OAGIS n. Acronym for Open Applications Group Integration Specification. A set of XML-based specifications and standards designed to promote B2B e-commerce by providing interoperability between enterprise-scale applications and between companies. OAGIS includes business document specifications and definitions, business process scenarios, and templates for business forms such as invoices and requisitions. OAGIS is overseen by the Open Applications Group, Inc., a nonprofit consortium of software vendors and customers. See also OAGI.
OASIS n. Acronym for Organization for the Advancement of Structured Information Standards. A consortium of technology companies formed to develop guidelines for use of XML (Extensible Markup Language) and related information standards.
Oberon n. An extensible object-oriented language based on Modula-2, whose later versions support the .NET Framework. Also called: Active Oberon for .NET.
object n. 1. Short for object code (machine-readable code). 2. In object-oriented programming, a variable comprising both routines and data that is treated as a discrete entity. See also abstract data type, module (definition 1), object-oriented programming. 3. In graphics, a distinct entity. For example, a bouncing ball might be an object in a graphics program. 4. A single, runtime instance of object type that the operating system defines. Objects visible in user mode include event, file, I/O completion port, key, object directory, port, process, section, semaphore, symbolic link, thread, timer, and token objects. Many user-mode objects are implemented through the use of a corresponding kernel-mode object. Kernel-mode-only objects include adapter, APC, controller, device, device queue, DPC, driver, interrupt, mutex, and stream file objects.
object code n. The code, generated by a compiler or an assembler, that was translated from the source code of a program. The term most commonly refers to machine code that can be directly executed by the system s central processing unit (CPU), but it can also be assembly language source code or a variation of machine code. See also central processing unit.
object computer n. The computer that is the target of a specific communications attempt.
object database n. See object-oriented database.
Object Database Management Group n. An organization that promotes standards for object databases and defines interfaces to object databases. Acronym: ODMG. See also OMG.
object file n. A file containing object code, usually the output of a compiler or an assembler and the input for a linker. See also assembler, compiler (definition 2), linker, object code.
Objective-C n. An object-oriented version of the C language developed in 1984 by Brad Cox. It is most widely known for being the standard development language for the NeXT operating system. See also object-oriented programming.
object linking and embedding n. See OLE.
Object Management Architecture n. See OMA.
Object Management Group n. See OMG.
object model n. 1. The structural foundation for an object-oriented language, such as C++. This foundation includes such principles as abstraction, concurrency, encapsulation, hierarchy, persistence, polymorphism, and typing. See also abstract data type, object (definition 2), object-oriented programming, polymorphism. 2. The structural foundation for an object-oriented design. See also object-oriented design. 3. The structural foundation for an object-oriented application.
object module n. In programming, the object-code (compiled) version of a source-code file that is usually a collection of routines and is ready to be linked with other object modules. See also linker, module (definition 1), object code.
object-oriented adj. Of, pertaining to, or being a system or language that supports the use of objects. See also object (definition 2).
object-oriented analysis n. A procedure that identifies the component objects and system requirements of a system or process that involves computers and describes how they interact to perform specific tasks. The reuse of existing solutions is an objective of this sort of analysis. Object-oriented analysis generally precedes object-oriented design or object-oriented programming when a new object-oriented computer system or new software is developed. See also object (definition 2), object-oriented design, object-oriented programming.
object-oriented database n. A flexible database that supports the use of abstract data types, objects, and classes and that can store a wide range of data, often including sound, video, and graphics, in addition to text and numbers. Some object-oriented databases allow data retrieval procedures and rules for processing data to be stored along with the data or in place of the data. This allows the data to be stored in areas other than in the physical database, which is often desirable when the data files are large, such as those for video files. Acronym: OODB. See also abstract data type, class, object (definition 2). Compare relational database.
object-oriented design n. A modular approach to creating a software product or computer system, in which the modules (objects) can be easily and affordably adapted to meet new needs. Object-oriented design generally comes after object-oriented analysis of the product or system and before any actual programming. See also object (definition 2), object-oriented analysis.
object-oriented graphics n. Computer graphics that are based on the use of graphics primitives, such as lines, curves, circles, and squares. Object-oriented graphics, used in applications such as computer-aided design and drawing and illustration programs, describe an image mathematically as a set of instructions for creating the objects in the image. This approach contrasts with the use of bitmapped graphics, in which a graphic is represented as a group of black-and-white or colored dots arranged in a certain pattern. Object-oriented graphics enable the user to manipulate objects as units. Because objects are described mathematically, object-oriented graphics can be layered, rotated, and magnified relatively easily. Also called: structured graphics. See also graphics primitive. Compare bitmapped graphics, paint program.
object-oriented interface n. A user interface in which elements of the system are represented by visible screen entities, such as icons, that are used to manipulate the system elements. Object-oriented display interfaces do not necessarily imply any relation to object-oriented programming. See also object-oriented graphics.
object-oriented operating system n. An operating system based on objects and designed in a way that facilitates software development by third parties, using an object-oriented design. See also object (definition 2), object-oriented design.
object-oriented programming n. A programming paradigm in which a program is viewed as a collection of discrete objects that are self-contained collections of data structures and routines that interact with other objects. Acronym: OOP. See also C++, object (definition 2), Objective-C.
Object Pascal n. An object-oriented derivative of Pascal. See also Pascal.
object-relational server n. A database server that supports object-oriented management of complex data types in a relational database. See also database server, relational database.
object request broker n. See ORB.
object wrapper n. In object-oriented applications, a means of encapsulating a set of services provided by a non-object-oriented application so that the encapsulated services can be treated as an object. See also object (definition 2).
oblique adj. Describing a style of text created by slanting a roman font to simulate italics when a true italic font isn t available on the computer or printer. See also font, italic, roman.
OC3 n. Short for optical carrier 3. One of several optical signal circuits used in the SONET high-speed fiberoptic data transmission system. OC3 carries a signal of 155.52 Mbps, the minimum transmission speed for which SONET and the European standard, SDH, are fully interoperable. See also SONET.
OCR n. See optical character recognition.
octal n. The base-8 number system consisting of the digits 0 through 7, from the Latin octo, meaning eight. The octal system is used in programming as a compact means of representing binary numbers. See also base (definition 2).
octet n. A unit of data that consists of exactly 8 bits, regardless of the number of bits a computer uses to represent a small amount of information such as a character. Compare byte.
OCX n. Short for OLE custom control. A software module based on OLE and COM technologies that, when called by an application, produces a control that adds some desired feature to the application. OCX technology is portable across platforms, works on both 16-bit and 32-bit operating systems, and can be used with many applications. It is the successor to VBX (Visual Basic custom control) technology, which supported only Visual Basic applications, and is the basis for ActiveX controls. OCXs have, in fact, been superseded by ActiveX controls, which are much smaller and therefore work much better over the Internet. See also ActiveX control, COM (definition 2), control (definition 2), OLE, VBX, Visual Basic.
ODBC n. Acronym for Open Database Connectivity. In the Microsoft WOSA (Windows Open System Architecture) structure, an interface providing a common language for Windows applications to gain access to a database on a network. See also WOSA.
ODBC driver n. Short for Open Database Connectivity driver. A program file used to connect to a particular database. Each database program, such as Access or dBASE, or database management system, such as SQL Server, requires a different driver.
ODBMG n. See Object Database Management Group.
odd parity n. See parity.
ODI n. Acronym for Open Data-link Interface. A specification developed by Novell to enable a network interface card (NIC) to support multiple protocols, such as TCP/IP and IPX/SPX. ODI also simplifies development of device drivers by eliminating concern about the particular protocol to be used in transferring information over the network. ODI is comparable in some ways to the Network Driver Interface Specification, or NDIS. See also NDIS, network adapter.
ODMA n. Acronym for Open Document Management API. A specification for a standard application program interface that enables desktop applications, such as Microsoft Word, to interact seamlessly with specialized document management systems (DMS) installed on network servers. The ODMA specification is the property of the Association for Information & Image Management (AIIM). See also API, document management system.
OEM n. See original equipment manufacturer.
OFC n. See Open Financial Connectivity.
Office n. Microsoft s family of individual and business application software suites for the Windows and Macintosh platforms. Office is built around three core products: Word for word processing, Excel for spreadsheets, and Outlook for e-mail and collaboration. Office XP, the most recent version for the Windows platform, is available in several versions: the Office XP Standard or Standard for Students and Teachers version, which includes Word, Excel, Outlook, and PowerPoint; the Office XP Professional version, which adds Access; Office XP Developer, which includes Word, Excel, Outlook, PowerPoint, Access, FrontPage, Microsoft s new SharePoint Team Services collaboration and team Web solution, and Developer Tools; and finally, Office XP Professional Special Edition, which offers all the programs in Office XP Professional plus FrontPage, SharePoint Team Services, Publisher, and IntelliMouse Explorer. Office v. X for Mac is the most recent version for the Macintosh and includes Word, Entourage (for e-mail and collaboration), Excel, and PowerPoint. See the table.
Product Function Platform Word Word processing Windows, Macintosh Excel Spreadsheets Windows, Macintosh Outlook E-mail, collaboration Windows Entourage E-mail, collaboration Macintosh Publisher Desktop publishing Windows Access Database management Windows PowerPoint Presentation graphics Windows, Macintosh FrontPage Web site creation Windows SharePoint Team Services Team Web solution Windows
office automation n. The use of electronic and communications devices, such as computers, modems, and fax machines and any associated software, to perform office functions mechanically rather than manually.
offline adj. 1. In reference to a computing device or a program, unable to communicate with or be controlled by a computer. Compare online (definition 1). 2. In reference to one or more computers, being disconnected from a network. Compare online (definition 2). 3. Colloquially, a reference to moving a discussion between interested parties to a later, more appropriate, time. For example, We can talk about this offline. Let s get back on topic now.
offline navigator n. Software designed to download e-mail, Web pages, or newsgroup articles or postings from other online forums and save them locally to a disk, where they can be browsed without the user paying the cost of idle time while being connected to the Internet or an online information service. Also called: offline reader.
offline reader n. See offline navigator.
offline storage n. A storage resource, such as a disk, that is not currently available to the system.
offload vb. To assume part of the processing demand from another device. For example, some LAN-attached gateways can offload TCP/IP processing from the host machine, thereby freeing up significant processing capacity in the CPU. See also central processing unit, gateway, host, TCP/IP.
offset n. In relative addressing methods, a number that tells how far from a starting point a particular item is located. See also relative address.
off-the-shelf adj. Ready-to-use; packaged. The term can refer to hardware or software.
ohm n. The unit of measure for electrical resistance. A resistance of 1 ohm will pass 1 ampere of current when a voltage of 1 volt is applied.
OLAP n. See OLAP database.
OLAP database n. Short for online analytical processing database. A relational database system capable of handling queries more complex than those handled by standard relational databases, through multidimensional access to data (viewing the data by several different criteria), intensive calculation capability, and specialized indexing techniques. See also database, query (definition 1), relational database.
OLAP provider n. A set of software that provides access to a particular type of OLAP database. This software can include a data source driver and other client software that is necessary to connect to a database. See also OLAP database.
OLE n. Acronym for object linking and embedding. A technology for transferring and sharing information among applications. When an object, such as an image file created with a paint program, is linked to a compound document, such as a spreadsheet or a document created with a word processing program, the document contains only a reference to the object; any changes made to the contents of a linked object will be seen in the compound document. When an object is embedded in a compound document, the document contains a copy of the object; any changes made to the contents of the original object will not be seen in the compound document unless the embedded object is updated.
OLED n. Acronym for Organic Light-Emitting Device. Technology developed for the production of thin, lightweight digital displays. An OLED features a series of thin organic films between two conductors. When current is applied, bright light is emitted. OLED displays are lightweight, durable, and power-efficient.
OLE Database n. An application programming interface developed by Microsoft for accessing databases. OLE Database is an open specification that can interface with all types of data files on a computer network. Acronym: OLE DB.
OLTP n. Acronym for online transaction processing. A system for processing transactions as soon as the computer receives them and updating master files immediately in a database management system. OLTP is useful in financial record keeping and inventory tracking. See also database management system, transaction processing. Compare batch processing (definition 3).
OM-1 n. See OpenMPEG Consortium.
OMA n. Acronym for Object Management Architecture. A definition developed by the Object Management Group (OMG) for object-oriented distributed processing. OMA includes the Common Object Request Broker Architecture (CORBA). See also CORBA, OMG.
OMG n. Acronym for Object Management Group. A nonprofit organization that provides a framework of standards for object-oriented interfaces. The open and nonproprietary architecture developed and managed by the OMG allows developers to work with a large toolkit of standard components in building applications with a solid common foundation. The OMG was formed in 1989 by a group of software developers and system vendors and now has more than six hundred member companies.
on-board computer n. A computer that resides within another device.
on-chip cache n. See L1 cache.
on-demand publishing point n. A type of publishing point that streams content in such a way that the client can control (start, stop, pause, fast-forward, or rewind) the content. Typically, the on-demand content is a Windows Media file or a directory of files. Content streamed from an on-demand publishing point is always delivered as a unicast stream. Formerly called a station.
one-off n. 1. A product that is produced one at a time, instead of being mass produced. 2. A CD-ROM created on a CD-R machine, which can create only one copy of a CD-ROM at a time.
one-pass compiler n. A compiler that needs to read through a source file only once to produce the object code. The syntax of some languages makes it impossible to write a one-pass compiler for those languages. See also compiler (definition 2).
one s complement n. A number in the binary (base-2) system that is the complement of another number. See also complement.
one-to-many relationship n. An association between two tables in which the primary key value of each record in the primary table corresponds to the value in the matching field or fields of many records in the related table.
one-to-many replication n. A server configuration allowing replication of data from one or more large servers to a greater number of smaller servers.
one-to-one relationship n. An association between two tables in which the primary key value of each record in the primary table corresponds to the value in the matching field or fields of one and only one record in the related table.
one-way trust n. A type of trust relationship in which only one of the two domains trusts the other domain. For example, domain A trusts domain B and domain B does not trust domain A. All one-way trusts are nontransitive. See also transitive trust, two-way trust.
onion routing n. An anonymous communication technique first developed by the U.S. Navy, in which a message is wrapped in layers of encryption and passed through several intermediate stations to obscure its point of origin. In onion routing, data packets are sent through a complex network of routers, each of which opens an anonymous connection to the next, until it reaches its destination. When the packet is received by the first onion router, it is encrypted once for each additional router it will pass through. Each subsequent onion router unwraps one layer of encryption until the message reaches its destination as plain text.
online adj. 1. In reference to a computing device or a program, activated and ready for operation; capable of communicating with or being controlled by a computer. Compare offline (definition 1). 2. In reference to one or more computers, connected to a network. Compare offline (definition 2). 3. In reference to a user, currently connected to the Internet, an online service, or a BBS or using a modem to connect to another modem. 4. In reference to a user, being able to connect to the Internet, an online service, or a BBS by virtue of having an account that gives one access.
online analytical processing n. See OLAP database.
online community n. 1. All users of the Internet and World Wide Web collectively. 2. A local community that places political forums on line for the discussion of local government or issues of public concern. 3. Members of a specific newsgroup, mailing list, MUD, BBS, or other online forum or group. See also BBS (definition 1), mailing list, MUD, newsgroup.
online game n. A game that is meant to be played while connected to the Internet, intranet, or other network, with one or more other people simultaneously connected. Online games allow gamers to interact with other players without having their physical presence necessary. See also computer game.
online help n. See help.
online information service n. A business that provides access to databases, file archives, conferences, chat groups, and other forms of information through dial-up, or dedicated communications links, or through the Internet. Most online information services also offer access to the Internet connections along with their own proprietary services. The largest consumer online information services in the U.S. are America Online, CompuServe, and MSN.
Online Privacy Alliance n. See OPA.
online service n. See online information service.
online state n. The state of a modem when it is communicating with another modem. Compare command state.
online transaction processing n. See OLTP.
on-screen keyboard n. An interactive keyboard that appears as a graphical image on the display screen of a computing device. A user spells words by tapping the letters on the screen with a stylus. On-screen keyboards appear primarily on personal digital assistants (PDAs) and other handheld computing devices that are too small to contain a traditional keyboard.
on the fly adv. Doing a task or process as needed without suspending or disturbing normal operations. For example, it is often said that an HTML document can be edited on the fly because its content can be revised without the need to completely shut down or re-create the Web site on which it resides. See also HTML document, Web site.
OO adj. See object-oriented.
OOP n. See object-oriented programming.
OPA n. Acronym for Online Privacy Alliance. An organization of over eighty Internet companies and trade associations created to be the voice of the industry on digital privacy issues. The OPA stresses the need for consumer trust and encourages online businesses to post privacy policies. The OPA created a set of guidelines for privacy policies that have become the industry standard.
opacity n. The quality that defines how much light passes through an object s pixels. If an object is 100 percent opaque, no light passes through it.
opcode n. See operation code.
open1 adj. Of, pertaining to, or providing accessibility. For example, an open file is one that can be used because a program has issued an open file command to the operating system.
open2 vb. To make an object, such as a file, accessible.
Open Applications Group, Inc. n. See OAGI.
open architecture n. 1. Any computer or peripheral design that has published specifications. A published specification lets third parties develop add-on hardware for a computer or device. Compare closed architecture (definition 1). 2. A design that provides for expansion slots on the motherboard, thereby allowing the addition of boards to enhance or customize a system. Compare closed architecture (definition 2).
OpenCyc n. An open source artificial intelligence platform. OpenCyc forms the foundation of knowledge-dependent applications such as speech understanding, database integration, and e-mail routing and prioritizing. OpenCyc development is administered through OpenCyc.org.
Open Data-link Interface n. See ODI.
OpenDoc n. An object-oriented application programming interface (API) that enables multiple independent programs (component software) on several platforms to work together on a single document (compound document). Similar to OLE, OpenDoc allows images, sound, video, other documents, and other files to be embedded or linked to the document. OpenDoc is supported by an alliance that includes Apple, IBM, the Object Management Group, and the X Consortium. See also application programming interface, component software. Compare ActiveX, OLE.
Open Document Management API n. See ODMA.
open file n. A file that can be read from, written to, or both. A program must first open a file before the file s contents can be used, and it must close the file when done. See also open2.
Open Financial Connectivity n. The Microsoft specification for an interface between electronic banking services and Microsoft Money personal finance software. Acronym: OFC.
OpenGL n. An industry standard application programming interface (API) for 3D graphics rendering and 3D hardware acceleration. OpenGL is cross-platform and is available for all major operating systems.
Open Group n. A consortium of computer hardware and software manufacturers and users from industry, government, and academia that is dedicated to the advancement of multi-vendor information systems. The Open Group was formed in 1996 as a consolidation of the Open Software Foundation and X/Open Company Limited.
OpenMPEG Consortium n. An international organization of hardware and software developers for promoting the use of the MPEG standards. Acronym: OM-1. See also MPEG.
Open Prepress Interface n. See OPI.
Open Profiling Standard n. An Internet personalization and privacy specification submitted for consideration to the World Wide Web Consortium by Netscape Communications Corporation, Firefly Network, Inc., and VeriSign, Inc. Open Profiling Standard (OPS) enables users to customize online services while protecting their privacy. To achieve personalization and privacy concomitantly, OPS is based on the concept of a Personal Profile, which is stored on the individual s computer and contains the user s unique identification, demographic and contact data, and possibly content preferences. This information remains under the user s control and can be released wholly or in part to the requesting site. Acronym: OPS. See also cookie, digital certificate.
open shop n. A computer facility that is open to users and not restricted to programmers or other personnel. An open shop is one in which people can work on or attempt to solve computer problems on their own rather than handing them over to a specialist.
Open Shortest Path First n. See OSPF.
Open Software Foundation n. See OSF.
open source n. The practice of making the source code (program instructions) for a software product freely available, at no cost, to interested users and developers, even though they were not involved in creating the original product. The distributors of open source software expect and encourage users and outside programmers to examine the code in order to identify problems, and to modify the code with suggested improvements and enhancements. Widely used open source products include the Linux operating system and the Apache Web server.
open standard n. A publicly available set of specifications describing the characteristics of a hardware device or software program. Open standards are published to encourage interoperability and thereby help popularize new technologies. See also standard (definition 2).
open system n. 1. In communications, a computer network designed to incorporate all devices regardless of the manufacturer or model that can use the same communications facilities and protocols. 2. In reference to computer hardware or software, a system that can accept add-ons produced by third-party suppliers. See also open architecture (definition 1).
Open Systems Interconnection reference model n. See ISO/OSI reference model.
OpenType n. A collaborative initiative by Microsoft and Adobe to unify support for Microsoft TrueType and Adobe PostScript Type 1 fonts. The OpenType font format enables font creators and users to work with the font type that best suits their needs without having to worry about whether the font is based on TrueType or PostScript technology. Also called: TrueType Open version 2. See also PostScript font, TrueType.
Opera n. A Web browser developed by Opera Software S/A. Opera is notable for its strict W3C standards support. Opera is often chosen by Web developers to test Web sites for W3C compliance. See also W3C, Web browser.
operand n. The object of a mathematical operation or a computer instruction.
operating system n. The software that controls the allocation and usage of hardware resources such as memory, central processing unit (CPU) time, disk space, and peripheral devices. The operating system is the foundation software on which applications depend. Popular operating systems include Windows 98, Windows NT, Mac OS, and UNIX. Acronym: OS. Also called: executive.
operation n. 1. A specific action carried out by a computer in the process of executing a program. 2. In mathematics, an action performed on a set of entities that produces a new entity. Examples of mathematical operations are addition and subtraction.
operation code n. The portion of a machine language or assembly language instruction that specifies the type of instruction and the structure of the data on which it operates. Also called: opcode. See also assembly language, machine code.
operations research n. The use of mathematical and scientific approaches to analyze and improve efficiency in business, management, government, and other areas. Developed around the beginning of World War II, operations research was initially used to improve military operations during the war. The practice later spread to business and industry as a means of breaking down systems and procedures and studying their parts and interactions to improve overall performance. Operations research involves use of the critical path method, statistics, probability, and information theory.
operator n. 1. In mathematics and in programming and computer applications, a symbol or other character indicating an operation that acts on one or more elements. See also binary, unary. 2. A person who controls a machine or system such as a computer or telephone switchboard.
operator associativity n. A characteristic of operators that determines the order of evaluation in an expression when adjacent operators have equal precedence. The two possibilities are left to right and right to left. The associativity for most operators is left to right. See also expression, operator (definition 1), operator precedence.
operator overloading n. The assignment of more than one function to a particular operator, with the implication that the operation performed will vary depending on the data type (operands) involved. Some languages, such as Ada and C++, specifically allow for operator overloading. See also Ada, C++, function overloading, operator (definition 1).
operator precedence n. The priority of the various operators when more than one is used in an expression. In the absence of parentheses, operations with higher precedence are performed first. See also expression, operator (definition 1), operator associativity.
OPI n. Acronym for Open Prepress Interface. A format for preparing digital publication text and graphics for printing, introduced by Aldus (now Adobe), creating a low-resolution graphic for layout and a high-resolution graphic for print. Depending on the method used, the OPI process creates a single file that allows for color layer extraction though a desktop color separation program or creates multiple color-separated files when using DCS (Desktop Color Separation). Compare DCS.
OPS n. See Open Profiling Standard.
optical character recognition n. The process in which an electronic device examines printed characters on paper and determines their shapes by detecting patterns of dark and light. Once the scanner or reader has determined the shapes, character recognition methods pattern matching with stored sets of characters are used to translate the shapes into computer text. Acronym: OCR. See also character recognition. Compare magnetic-ink character recognition.
optical communications n. The use of light and of light-transmitting technology, such as optical fibers and lasers, in sending and receiving data, images, or sound.
optical disc n. See compact disc.
optical drive n. A disk drive that reads and often can write data on optical (compact) discs. Examples of optical drives include CD-ROM drives and WORM disk drives. See also CD-ROM drive, compact disc, WORM.
optical fiber n. A thin strand of transparent material used to carry optical signals. Optical fibers are constructed from special kinds of glass and plastic, and they are designed so that a beam of light introduced at one end will remain within the fiber, reflecting off the inner surfaces as it travels down the length of the fiber. Optical fibers are inexpensive, compact, and lightweight and are often packaged many hundred to a single cable. See also fiber optics.
optical mouse n. 1. A type of mouse that uses a CMOS digital camera and a digital signal processor to detect motion. The camera photographs the surface over which the mouse moves 1500 times per second, and the digital signal processor uses the photographs to convert the mouse movement into onscreen movements of the cursor. IntelliMouse Explorer and IntelliMouse with IntelliEye, two optical mouse models with no moving parts and requiring no special mouse pad, were introduced by Microsoft in 1999. See also mouse. 2. A type of mouse that uses a pair of light-emitting diodes (LEDs) and a special reflective grid pad to detect motion. The two lights are of different colors, and the special mouse pad has a grid of lines in the same colors, one color for vertical lines and another for horizontal lines. Light detectors paired with the LEDs sense when a colored light passes over a line of the same color, indicating the direction of movement. See also mouse. Compare mechanical mouse, optomechanical mouse.
optical reader n. A device that reads text from printed paper by detecting the pattern of light and dark on a page and then applying optical character recognition methods to identify the characters. See also optical character recognition.
optical recognition n. See optical character recognition.
optical scanner n. An input device that uses light-sensing equipment to scan paper or another medium, translating the pattern of light and dark or color into a digital signal that can be manipulated by either optical character recognition software or graphics software. Scanners have different methods for holding the input medium, including flatbed, whereby the medium is held on a piece of glass; sheet-fed, whereby sheets of paper are pulled over a stationary scanning mechanism; handheld, whereby the user moves the device over the document to be scanned; and overhead, whereby the document is placed face up on a stationary bed below a small tower, which moves across the page. Compare magnetic-ink character recognition, spatial digitizer.
optical switching n. A technology in which transmissions are sent as light from origin to destination. With optical switching, transmissions are switched through banks of adjustable, circular millimeter mirrors at cross connections, meaning signals don t need to be converted from light to electronic and back during transmission. When used with wave-division multiplexing (WDM), all-optical traffic may be 100 times faster than electrical transmission. See also photonics.
optimization n. 1. In programming, the process of producing more efficient (smaller or faster) programs through selection and design of data structures, algorithms, and instruction sequences. 2. The process of a compiler or assembler in producing efficient executable code. See also optimizing compiler.
optimize vb. 1. In Web design functions, to reduce the file size of a photo or graphic to allow faster loading. Files are typically optimized through a combination of means such as reducing overall image quality and fine-tuning color information. 2. To fine-tune an application for improved performance. See also optimization.
optimizer n. A program or device that improves the performance of a computer, network, or other device or system. For example, a disk optimizer program reduces file access time.
optimizing compiler n. A compiler that analyzes its output (assembly language or machine code) to produce more efficient (smaller or faster) instruction sequences.
opt-in vb. To choose to receive certain services or features offered by an e-business. With the opt-in process, a user is not automatically enrolled in services or features. The user must choose to enroll in a service or feature.
optional hyphen n. See hyphen.
Option key n. A key on Apple Macintosh keyboards that, when pressed in combination with another key, produces special characters graphics, such as boxes; international characters, such as currency symbols; and special punctuation marks, such as en dashes and em dashes. The Option key serves a purpose similar to that of the Control key or the Alt key on IBM and compatible keyboards in that it changes the meaning of the key with which it is used.
Options n. See Preferences.
optoelectronics n. The branch of electronics in which the properties and behavior of light are studied. Optoelectronics deals with electronic devices that generate, sense, transmit, and modulate electromagnetic radiation in the infrared, visible, and ultraviolet portions of the electromagnetic spectrum.
optomechanical mouse n. A type of mouse in which motion is translated into directional signals through a combination of optical and mechanical means. The optical portion includes pairs of light-emitting diodes (LEDs) and matching sensors; the mechanical portion consists of rotating wheels with cutout slits. When the mouse is moved, the wheels turn and the light from the LEDs either passes through the slits and strikes a light sensor or is blocked by the solid portions of the wheels. These changes in light contact are detected by the pairs of sensors and interpreted as indications of movement. Because the sensors are slightly out of phase with one another, the direction of movement is determined based on which sensor is the first to regain light contact. Because it uses optical equipment instead of mechanical parts, an optomechanical mouse eliminates the need for many of the wear-related repairs and maintenance necessary with purely mechanical mice, but it does not require the special operating surfaces associated with optical mice. See the illustration. See also mouse. Compare mechanical mouse, optical mouse. Optomechanical mouse.
opt-out vb. To choose not to receive certain services or features offered by an e-business. Some e-businesses automatically enroll users in a predetermined range of services, but allow users to opt-out of features in which they do not choose to participate.
OR n. A logical operation for combining two bits (0 or 1) or two Boolean values (false or true). If one or both values are 1 (true), it returns the value 1 (true). See the table.
a b a OR b 0 0 0 0 1 1 1 0 1 1 1 1
Orange Book n. 1. A U.S. Department of Defense standards document entitled Trusted Computer System Evaluation Criteria, DOD standard 5200.28-STD, December, 1985, which defines a system of ratings from A1 (most secure) to D (least secure), indicating the ability of a computer system to protect sensitive information. Compare Red Book (definition 1). 2. A specifications book written by the Sony and Philips Corporations, covering the compact disc write-once formats (CD-R, PhotoCD). See also CD-R, ISO 9660, PhotoCD. Compare Green Book, Red Book (definition 2).
ORB n. Acronym for object request broker. In client/server applications, an interface to which the client makes a request for an object. The ORB directs the request to the server containing the object and then returns the resulting values to the client. See also client (definition 1), CORBA.
order1 n. 1. In computing, the relative significance of a digit or byte. High-order refers to the most significant (usually leftmost) digit or byte; low-order refers to the least significant (usually rightmost) digit or byte. 2. The magnitude of a database in terms of the number of fields it contains. 3. The sequence in which arithmetic operations are performed.
order2 vb. To arrange in a sequence, such as alphabetic or numeric.
ordinal number n. A number whose form indicates position in an ordered sequence of items, such as first, third, or twentieth. Compare cardinal number.
.org n. In the Internet s Domain Name System, the top-level domain that identifies addresses operated by organizations that do not fit any of the other standard domains. For instance, the Public Broadcasting System (PBS) is neither a commercial, for-profit corporation (.com) nor an educational institution with enrolled students (.edu), so it has the Internet address pbs.org. The designation .org appears at the end of the address. See also DNS (definition 1), domain (definition 3). Compare .com, .edu, .gov, .mil, .net.
Organic Light-Emitting Device n. See OLED.
Organization for the Advancement of Structured Information Standards n. See OASIS.
OR gate n. One of the three basic logic gates (with AND and NOT) from which all digital systems can be built. The output of an OR circuit is true (1) if any input is true. See also AND gate, gate (definition 1), NOT gate.
orientation n. See landscape mode, portrait mode.
original equipment manufacturer n. The maker of a piece of equipment. In making computers and related equipment, manufacturers of original equipment typically purchase components from other manufacturers of original equipment, integrate them into their own products, and then sell the products to the public. Acronym: OEM. Compare value-added reseller.
original Macintosh keyboard n. The keyboard supplied as standard equipment with the 128-KB Apple Macintosh and the Mac 512K. The original Macintosh keyboard is small and has no numeric keypad or function keys. Also, because the overall design goal was that the Macintosh should feel familiar, the only elements of this 58-key keyboard that differ from a typewriter keyboard are the Option keys at both ends of the bottom row, the Command key to the left of the Spacebar, and the Enter key to the right of the Spacebar.
orphan n. The first line of a paragraph printed alone at the bottom of a page or column of text, or the last line of a paragraph printed alone at the top of a page or column. Orphans are visually unattractive and thus undesirable in printed materials. Compare widow.
orphan file n. A file that remains on a system after it has ceased to be of use. For example, a file may be created to support a particular application but may remain after the application has been removed.
OS n. See operating system.
OS/2 n. Short for Operating System/2. A protected-mode, virtual-memory, multitasking operating system for personal computers based on the Intel 80286, 80386, i486, and Pentium processors. OS/2 can run most MS-DOS applications and can read all MS-DOS disks. OS/2 s Presentation Manager provides a graphical user interface. The latest version, known as OS/2 Warp 4, is a 32-bit operating system that provides networking, Internet, and Java support, as well as speech recognition technology. OS/2 was initially developed as a joint project of Microsoft and IBM but later became an IBM product. See also protected mode, virtual memory.
oscillation n. A periodic change or alternation. In electronics, oscillation refers to a periodic change in an electrical signal.
oscillator n. An electronic circuit that produces a periodically varying output at a controlled frequency. Oscillators, an important type of electronic circuit, can be designed to provide a constant or an adjustable output. Some oscillator circuits use a quartz crystal to generate a stable frequency. Personal computers use an oscillator circuit to provide the clock frequency typically 1 to 200 megahertz (MHz) that drives the processor and other circuits.
oscilloscope n. A test and measurement instrument that provides a visual display for an electrical signal. Most commonly, oscilloscopes are used to create a display of voltage over time. Also called: cathode-ray oscilloscope.
OSF n. Acronym for Open Software Foundation. A nonprofit consortium of firms (including DEC, Hewlett-Packard, and IBM), formed in 1988, that promotes standards and specifications for programs operating under UNIX and licenses software (as source code) to its members. OSF s products include the Distributed Computing Environment, the graphical user interface Motif, and the OSF/1 operating system (a variant of UNIX).
OSI n. See ISO/OSI reference model.
OSI protocol stack n. The set of protocols based on and corresponding to the ISO/OSI reference model.
OSI reference model n. See ISO/OSI reference model.
OSPF n. Acronym for Open Shortest Path First. A routing protocol for IP networks, such as the Internet, that allows a router to calculate the shortest path to each node for sending messages. The router sends information on the nodes it is linked to, called link-state advertisements, to other routers on the network to accumulate link-state information to make its calculations. See also communications protocol, node (definition 2), path (definition 1), router.
OS X n. See Mac OS X.
OTOH n. Acronym for on the other hand. A shorthand expression often used in e-mail, Internet news, and discussion groups.
Outbox n. In many e-mail applications, the default mailbox where the program stores outgoing messages. See also e-mail(definition 1), mailbox. Compare Inbox.
outdent n. See hanging indent.
outer join n. In database management, an operator in relational algebra. An outer join performs an extended join operation in which the tuples (rows) in one relation (table) that have no counterpart in the second relation appear in the resulting relation concatenated with all null values. Compare inner join.
outline font n. A font (type design) stored in a computer or printer as a set of outlines for drawing each of the alphabetic and other characters in a character set. Outline fonts are templates rather than actual patterns of dots and are scaled up or down to match a particular type size. Such fonts are most often used for printing, as is the case with most PostScript fonts on a PostScript-compatible laser printer and TrueType fonts. Compare bitmapped font, screen font, stroke font.
Outlook n. Microsoft s messaging and collaboration application software. A member of the Microsoft Office suite, Outlook includes e-mail, an integrated calendar, and contact-management and task-management features, and it also provides support for building customized tools, such as special-purpose forms, for collaborative functions.
out-of-band signaling n. Transmission of some signals, such as control information, on frequencies outside the bandwidth available for voice or data transfer on a communications channel. Compare in-band signaling.
output1 n. The results of processing, whether sent to the screen or printer, stored on disk as a file, or sent to another computer in a network.
output2 vb. To send out data by a computer or sound by a speaker.
output area n. See output buffer.
output-bound n. See input/output-bound.
output buffer n. A portion of memory set aside for temporary storage of information, leaving main memory for storage, display, printing, or transmission. See also buffer.
output channel n. See channel (definition 1), input/output channel.
output simulation n. A feature of color management applications in which a computer display is calibrated to help predict the results of printing a graphics file on a specific device. Also called: soft proofing.
output stream n. A flow of information that leaves a computer system and is associated with a particular task or destination. In programming, an output stream can be a series of characters sent from the computer s memory to a display or to a disk file. Compare input stream.
outsourcing n. The assignment of tasks to independent contractors, such as individual consultants or service bureaus. Tasks such as data entry and programming are often performed via outsourcing.
OverDrive n. A type of microprocessor from Intel designed to replace a computer s existing i486SX or i486DX microprocessor. The OverDrive is functionally identical to Intel s i486DX2 microprocessor, but it is an end-user product, whereas the i486DX2 is sold only to computer manufacturers who build it into their own systems. Upgrading a system with an OverDrive processor differs from system to system, and some systems might not be able to support an OverDrive processor. See also i486DX, i486SL, i486SX, microprocessor. Compare i486DX2.
overflow n. 1. Generally, the condition that occurs when data resulting from input or processing requires more bits than have been provided in hardware or software to store the data. Examples of overflow include a floating-point operation whose result is too large for the number of bits allowed for the exponent, a string that exceeds the bounds of the array allocated for it, and an integer operation whose result contains too many bits for the register into which it is to be stored. See also overflow error. Compare underflow. 2. The part of a data item that cannot be stored because the data exceeds the capacity of the available data structure.
overflow error n. An error that arises when a number, often the result of an arithmetic operation, is too large to be contained in the data structure that a program provides for it.
overhead n. Work or information that provides support possibly critical support for a computing process but is not an intrinsic part of the operation or data. Overhead often adds to processing time but is generally necessary.
overlaid windows n. See cascading windows.
overlapped communication operation n. The performance of two distinct communication operations simultaneously; for example, a simultaneous read/write operation. Windows CE does not support overlapped communication operation, but it does support multiple read/writes pending on a device.
overlay1 n. 1. A section of a program designed to reside on a designated storage device, such as a disk, and to be loaded into memory when needed, usually overwriting one or more overlays already in memory. Use of overlays allows large programs to fit into a limited amount of memory, but at the cost of speed. 2. A printed form positioned over a screen, tablet, or keyboard for identification of particular features. See also keyboard template.
overlay2 vb. 1. In computer graphics, to superimpose one graphic image over another. 2. In video, to superimpose a graphic image generated on a computer over video signals, either live or recorded.
overprint vb. The process of printing an element of one color over one of another color without removing, or knocking out, the material underneath. Compare knockout (definition 1).
override vb. To prevent something from happening in a program or in an operating system or to initiate another response. For example, a user can often override and thus abort a lengthy sorting procedure in a database program by pressing the Escape key.
overrun n. In information transfer, an error that occurs when a device receiving data cannot handle or make use of the information as rapidly as it arrives. See also input/output-bound.
overscan n. The part of a video signal sent to a raster display that controls the area outside the rectangle containing visual information. The overscan area is sometimes colored to form a border around the screen.
overshoot n. The phenomenon in which a system suffers from a time delay in responding to input and continues to change state even after it has reached the desired state. This situation requires that correcting input be made so that the system reaches the desired state. For example, the arm carrying the heads in a hard disk drive might move slightly past the desired track before it stops, requiring another signal to pull it back.
overstrike vb. To type or print one character directly over another so that the two occupy the same space on the page or screen.
overtype mode n. See overwrite mode.
overwrite mode n. A text-entry mode in which newly typed characters replace existing characters under or to the left of the cursor insertion point. Also called: overtype mode, typeover mode. Compare insert mode.
overwriting virus n. A type of virus that overwrites the host file it has infected, destroying the original data. Also called: overwrite virus.
Oz n. A concurrent, object-oriented programming language.
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