0-9 A B C D E F G H I J K L M N O P Q R S T U V W XYZ

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operable time:
The time during which a functional unit would yield correct result if it were operated.

An entity on which an operation is performed.

operate mode:
Synonym for compute mode.

operating environment:
The external surroundings of a program existing or expected to exist during its execution.

operating mode:
The manner in which data are processed.

operating system (OS):
Software that controls the execution of programs and that may provide services such as resource allocation, scheduling, input/output control, and data management. Although operating systems are predominantly software, partial implementations in firmware or hardware are possible.

(1) A well-defined action that, when applied to any permissible combination of known entities, produces a new entity; for example, the process of addition in arithmetic in adding 5 and 3 and obtaining 8, the numbers 5 and 3 are the operands, the number 8 is the result, and the plus sign is the operator indicating that the operation performed is addition. (2) A program step, usually specified by the operation part of an instruction, that is undertaken or executed by a computer; for example, extraction, comparison, shift, transfer.

operational amplifier:
An amplifier connected to external elements to perform specific operations or functions.

Knowledge compilation by conversion from a declarative form into a procedural, that is, operational form; for example: converting the advice "don't get wet" into specific instructions by explaining how to avoid getting wet in a given situation. Contrast with analytic learning.

operation code:
The encoded representation of the operation part of a machine instructions. In an assembly language, BNZ might be used to designate the operation "branch if not zero", which might be ultimately represented in machine-code as a specific bit pattern. Synonymous with op code, instruction code.

operation code trap:
A specific modification of the operation part of a machine instruction that causes an interrupt when that machine instruction is executed.

operation exception:
An exception that occurs when a program encounters an invalid operation part.

operation field:
Synonym for operation part.

operation part:
The part of a machine instruction or microinstruction that specifies the operation to be performed. Synonymous with operation field.

operation table:
A table that defines an operation by listing all appropriate combinations of values of the operands and indicating the result for each of these combinations.

(1) In symbol manipulation, a symbol that represents the action to be performed in an operation. (2) A person who operates a machine.

operator console:
A functional unit containing devices that are used for communications between a computer operator and a data processing system.

operator control panel:
A functional unit that contains switches used to control a computer or part of it, and possibly containing indicators giving information about its functioning. An operator control panel may be part of an operator console or other operator-controlled device.

operator precedence:
An ordering rule defining the sequence of the application of operators within an expression. The ordering rule may specify the evaluation direction.

opportunistic planning:
A planning technique that includes the development of details based on availability of data (i.e., opportunity) as distinct from a more formally scheduled technique, such as in hierarchical planning.

opportunity study:
A study to examine a problem and determine whether or not it requires being solved during the time period under consideration.

optical character:
A graphic character printed or handwritten according to special rules to facilitate character recognition based on optical sensing.

optical character reader:
An input unit that reads characters by optical character recognition.

optical character recognition (OCR):
Character recognition based on optical sensing of the graphic characters.

optical disc:
Synonym for optical disk.

optical disk:
A disk that will accept and retain data in the form of marks in a recording layer, that can be read with an optical beam. According to their function, optical disks are categorized in rewritable (with phase change or magneto-optical technology), write-once (magneto-optical technology), WORM (with phase change, ablative or other technology), read-only (embossed technology). Synonymous with optical disc, digital optical disk.

optical disk cartridge (ODC):
An optical disk storage device consisting of a case containing an optical disk.

optical disk drive:
A disk drive for writing and/or reading data on an optical disk.

optical disk storage:
Optical storage using optical disks; for example: optical disk cartridge, optical disk drive.

optical fiber:
A transmission medium that consists of optical transparent filaments capable of conveying signals by optical means.

optical head:
In an optical disk drive, an assembly of optical components with the function of shaping and positioning an optical beam used for one or more functions of reading, writing, or erasing data on optical disks.

optical library:
Synonym for jukebox.

optical mark reading:
Synonym for mark scanning.

optical mouse:
A mouse whose movement is converted into signals by optical means.

optical processing:
Processing that uses optical methods, such as spatial filtering or interference effects.

optical scanner:
A scanner that uses optical processing for examining patterns.

optical storage:
Storage in which data is placed and/or retrieved by means of a focused optical beam; for example: optical tape storage, optical disk storage, optical card storage. Optical techniques may also be combined with other techniques, such as in magneto-optical storage.

Synonym for disjunction.

O/R address:
An attribute list that distinguishes one user, or distribution list, from another and defines the user's point of access to the message handling system or the distribution list's location. Synonymous with originator/recipient address. (Figure 66 - Examples of O/R addresses).

Orange Book:
Synonym for Trusted Computing System Evaluation Criteria.

An input unit in the shape of a small sphere, the size of a billiard ball, set in a base, like a joystick. Synonymous with orb input device.

orb input device:
Synonym for orb.

(1) To place items in an arrangement in accordance with specified rules. (2) A specified arrangement resulting from ordering. In contrast to a sequence, an order need not be linear; for example, the ordering of a hierarchy of items.

ordered tree:
A tree in which the order of the subtrees of each node is significant.

ordering bias:
The manner and degree by which the order of a set of items departs from random distribution. An ordering bias makes the effort necessary to order a set of items more than or less than the effort that would be required for a similar set with random distribution.

ordinal type:
A data type whose values represent members of an ordered countable set. Pascal ordinal types are "enumerated", "char", "integer", and "Boolean". Ada discrete types are either integer types or enumeration types. Contrast with nominal type.

organizational unit name:
An attribute or identifier of a unique designation of an organizational unit for the purpose of sending and receiving messages. (Figure 65 - Selected O/R address attributes). (Figure 66 - Examples of O/R addresses).

organization name:
An attribute or identifier of a unique designation for the purpose of sending and receiving messages. (Figure 65 - Selected O/R address attributes). (Figure 66 - Examples of O/R addresses).

OR gate:
Synonym for INCLUSIVE-OR gate.

The first transmittal step in which a direct user conveys a message or probe to its user agent, or an indirect user conveys a message or probe to the communication system that serves it.

(1) The user who creates, addresses, and usually sends a message. (2) The user that is the initial source of a message or probe. The originator usually creates a message or sends a probe.

originator/recipient address:
Synonym for O/R address.

originator/recipient name:
Synonym for O/R name.

O/R name:
An identifier by means of which a user can be designated as the originator, or by means of which a user or distribution list can be designated as a potential recipient of a message or probe. Synonymous with originator/recipient name. (Figure 66 - Examples of O/R addresses).

O-ROM disk:
A type of optical disk that provides for the whole of the disk surface to be prerecorded, and reproduced by stamping or other means, for reading without recourse to the magneto-optical effect.

In text processing, a first line of a paragraph that stands alone at the bottom of a column or page. Synonymous with orphan line. Contrast with widow.

orphan line:
Synonym for orphan.

operating system.

oscillating sort:
A merge sort in which the sorts and merges are performed alternately to form one sorted set.

open systems interconnection.

OSI environment.

OSI environment (OSIE):
An abstract representation of the set of concepts, elements, functions, services, and protocols, as defined by the OSI reference model and the derived specific standards which, when applied, enable communication among open systems.

OSI management:
The facilities to control, coordinate, and monitor resources that allow communication to take place in the OSI environment.

Open Systems Interconnection Reference Model.

A state of a functional unit in which it is not available due to external causes, such as power outages, fire, floods. Contrast with down time.

A mailbox that contains outgoing messages or messages that have been sent.

In flowcharting, a connector that indicates a point at which a flowline is broken for continuation at another point.

outline representation:
A wireframe representation of an object but with hidden lines removed.

Pertaining to a device, process, or channel involved in an output process, or to the associated data or states. The word "output" may be used in place of "output data", "output signal", or "output process" when such a usage is clear in a given context.

output channel:
A channel for conveying data from a device or gate.

output data:
(1) Data produced or to be produced by any component part of a computer. (2) Data that a data processing system, or any of its parts, transfers outside of that system or part.

output device:
Synonym for output unit.

output layer:
In artificial neural networks, a layer whose artificial neurons send signals to an external system. Synonymous with decision layer.

output medium:
A medium through which a system releases data. For example: sound from a loudspeaker.

output neuron:
An artificial neuron that sends signals to an external system.

output primitive:
Synonym for display element.

output process:
The process by which a functional unit transfers data outside of that unit.

output state:
A state that prevails on a specified output channel.

output subsystem:
That part of a process interface system that transfers data from the process computer system to a technical process.

output unit:
A device by which data can be conveyed out of a computer. Synonymous with output device.

(1) A condition that arises when the result of an operation exceeds the capacity of the numeration system used in a digital computer. (2) That portion of a word expressing the result of an arithmetic operation by which its word length exceeds the storage capacity of the intended storage device. (3) In calculators, the state in which the calculator is unable to accept or process the number of digits in the entry or the result.

overflow exception:
An exception that occurs when the result of an operation causes an overflow.

overhead bit:
An ancillary bit used for control purposes. Overhead bits are mainly used when the sending equipment carries out a process, particularly an aperiodic process, to ensure that the receiving equipment carries out the corresponding complementary process. They are normally added at regular intervals to a digital signal at the sending end and removed at the receiving end. Synonymous with service bit.

To load an overlay segment from external storage in such a manner that other portions of a program are overwritten.

overlay segment:
Each of several segments of a program that, one at a time, occupy the same area of main storage, when executed.

overlay supervisor:
A subprogram that controls the sequencing and positioning of overlay segments.

In programming, to assign more than one meaning to a lexical token; for example: the lexical token "+" can mean integer addition, real addition, set union, concatenation, etc.

overwritable disk:
An optical disk in which the data in specified areas can be written using one-beam overwrite.

(1) To write into an area of storage, thereby destroying the data previously stored in the same area. (2) In text processing, to replace existing text by entering new text into the same area.

owner record:
In a network model, that record which is superordinate to all the other records in a set.

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