object. (1.) In the Network Installation Management (NIM) environment, an entry in the NIM database that represents a machine, network, or resource. (2.) In Enhanced X-Windows, a software abstraction consisting of private data and private and public routines that operate on the private data. Users of the abstraction can interact with the object only through calls to the public routines of the objects. (3.) In ODM, an instance or member of an object class, conceptually similar to a structure that is a member or an array of structures. See also object class. (4.) In Pascal, synonymous with data object. (5.) In GL, synonymous with display list. A sequence of drawing commands that have been compiled into a unit. Conceptually, a display list is like a macro; it can be invoked multiple times simply by referring to its name. The object can be instantiated at different locations, sizes, and orientations by appropriate use of the transformation matrices. For instance, series of polygons arranged in the shape of a bolt can be compiled into an object. The bolt can then be drawn multiple times by invoking its display list. (6.) In NCS, an entity that is manipulated by well-defined operations. Disk files, printers, and array processors are examples of objects. Objects are accessed though interfaces. Every object has a type. (7.) In Ada language, an object contains a value. A program creates an object either by elaborating an object declaration or by evaluating an allocator. The declaration or allocator specifies a type for the object: the object can only contain values of that type. See also constant and variable. (8.) In C++, a region of storage. An object is created in C++ when a variable is defined or new is invoked. An object is destroyed when it goes out of scope. (9.) In XDS, anything in some ``world,'' generally the world of telecommunications and information processing or some part thereof, that is identifiable (can be named) and for which the DIB contains some information. (10.) In XOM, any of the complex information objects created, examined, modified, or destroyed by means of the interface. (11.) In SOM, an entity that has state (its data values) and behavior (its methods). An object is one of the elements of data and function that programs create, manipulate, pass as arguments, and so forth. An object is a way to encapsulate state and behavior. Encapsulation permits many aspects of the implementation of an object to change without affecting client programs that depend on the object's behavior. In SOM, objects are created by other objects called classes. (12.) In CDE, any logical piece of data that has associated behavior. For example, in File Manager, files, folders, actions, and applications are all considered objects. Each type of object has specific associated actions. Typically, each object is represented as an icon. See also type UUID .
object adapter (OA). In SOM, a CORBA term denoting the primary interface a server implementation uses to access ORB functions; in particular, it defines the mechanisms that a server uses to interact with DSOM, and vice versa. This includes server activation/deactivation, dispatching of methods, and authentication of the principal making a call. The basic object adapter described by CORBA is defined by the BOA (basic object adapter) abstract class; DSOM's primary object adapter implementation is provided by the SOMOA (SOM Object Adapter) class.
object class. In ODM, a stored collection of objects with the same definition, conceptually similar to an array of structures. See also object, terminal descriptor, and class.
Object Class Table (OCT). A recurring attribute of the directory schema with the description of the object classes permitted.
object code. (1.) Instructions that are able to be run by a machine, usually generated by a compiler from source code written in a higher-level language (such as C language). For programs that must be linked, object code consists of relocatable machine code. (2.) Output from a compiler or assembler that is itself executable machine code or is suitable for processing to produce executable machine code. Contrast with source code.
Object Data Manager (ODM). A data manager intended for the storage of system data. The ODM is used for many system management functions. Information used in many commands and SMIT functions is stored and maintained in the ODM as objects with associated characteristics.
object definition. See class.
object file. (1.) A member file in an object library. (2.) The primary output of a compiler or assembler, which can be processed by the binder (ld) to produce an executable file. The names of object files normally end in .o.
object handle. In graphical files, the start point of an arc or lines object.
object identifier. A value (distinguishable from all other such values) that is associated with an information object. (X.208)
object implementation. See implementation.
object instance. See instance and object.
object library. An area on a direct access storage device used to store object programs and routines.
object management. The creation, examination, modification, and deletion of potentially complex information objects.
object module. (1.) A portion of an object program suitable for input to a linkage editor. (2.) A set of instructions in machine language produced by a compiler from a source program. See also module.
object-oriented programming. A programming approach based on the concepts of data abstraction and inheritance. Unlike procedural programming techniques, object-oriented programming concentrates not on how something is accomplished but instead on what data objects comprise the problem and how they are manipulated.
object program. A fully compiled or assembled program that is ready to be loaded into the computer. Synonymous with target program.
object reference. In SOM, a CORBA term denoting the information needed to reliably identify a particular object. This concept is implemented in DSOM with a proxy object in a client process, or a SOMDObject in a server process. See also proxy object, server object, and SOMDObject.
object request broker (ORB). See ORB.
object space. The space in which a graphics object is defined. A convenient point is chosen as the origin and the object is defined relative to this point. When an object is rendered by a call to the callobj subroutine, it is rendered in modeling coordinates, and the object space becomes (for that moment) the same as the modeling space.
object type. In CDE, a desktop mechanism used to associate particular data files with the appropriate applications and actions. Object typing defines the criteria for typing the file (such as name or contents), the appearance (the icon used in File Manager), and the behavior of the object (for example, what happens when you double-click it).
object UUID. A UUID that identifies a particular object. Both the RPC runtime library and the Location Broker in NCS use object UUIDs to identify objects. See also Universal Unique Identifier (UUID).
obscure. In Enhanced X-Windows, (1.) A state of being for a window. A window is obscured if another window is in front of it making the obscured window partially viewable. Window B is obscured by window A if both are viewable InputOutput windows and A is higher in the global stacking order and the rectangle defined by the outside edges of A intersects the rectangle defined by the outside edges of B. Window borders are included in the calculation, and a window can be obscured and yet still have visible regions. (2.) An action one window does to another when it partially obstructs the viewing of the other. Window A obscures window B if both are viewable InputOutput windows, A is higher in the global stacking order, and the rectangle defined by the outside edges of A intersects the rectangle defined by the outside edges of B. Contrast with widget visibility.
occlude. In Enhanced X-Windows, (1.) A state of being for a window. A window is occluded if the view of it is completely obstructed by another window. Window B is occluded by window A if both are mapped, A is higher in the global stacking order, and if no part of the border of B is viewable. A fine distinction exists between "occlude" and "obscure." Window borders are included in the calculation. InputOnly windows never obscure other windows but can occlude other windows. (2.) An action one window does to another when it completely obstructs the view of the other. Contrast with widget visibility.
OCS. On-Card Sequencer.
OCT. See Object Class Table.
octal. (1.) A base-eight numbering system. (2.) Pertaining to a fixed-radix numeration having a radix of eight.
octal constant. The digit 0 (zero) followed by any digits 0 through 7.
octet. (1.) A group of 8 bits (also known as a byte). (2.) Pertaining to a selection, condition, or choice that has eight potential values or states. See also octet string.
octet string. A string made up of octets. See also octet.
ODM. See Object Data Manager.
off-hook. Activated, with regard to a telephone set. On a public switched system, a data set that automatically answers is said to go off-hook. Contrast with on-hook.
offline. (1.) Pertaining to the operation of a functional unit when it is not under the direct control of a computer. (2.) Neither controlled directly by nor communicating with the computer. Contrast with online.
offset. (1.) In Pascal, the selection mechanism in the SPACE data type; an element is selected by placing an integer value in brackets. The origin of SPACE is based on zero. (2.) In publications, the indentation of all lines of a block of text following the first line.
offset method resolution. The default mechanism for performing method resolution in SOM, because it is the fastest (nearly as fast as an ordinary procedure call). It is roughly equivalent to the C++ "virtual function" concept. Using offset method resolution requires that the name of the method to be invoked must be known at compile time, the name of the class that introduces the method must be known at compile time (although not necessarily by the programmer), and the method to be invoked must be a static method.
OIDL. The original language used for declaring SOM classes. The acronym stands for Object Interface Definition Language. OIDL is still supported by SOM release 2, but it does not include the ability to specify multiple inheritance classes.
OM. See XOM.
on-hook. Deactivated, in regard to a telephone set. A telephone not in use is "on-hook." Contrast with off-hook.
On Item help. In CDE, when you choose On Item from the Help menu, the cursor changes to a question mark and you can obtain information about a particular command, operation, dialog box, or control by clicking that object.
On Item Help control. In CDE, Front Panel control used to access item help information on the Front Panel.
one-copy serializable. The consistency property of the SOM Replication Framework which states that the concurrent execution of methods on a replicated object is equivalent to the serial execution of those same methods on a nonreplicated object.
one-way channel. In X.25 communications, a logical channel that allows incoming calls only or outgoing calls only. Contrast with two-way channel.
ones complement. The diminished radix complement in the pure binary numeration system. The ones complement is derived by replacing all of the zeros with ones and all of the ones with zeros in a binary number. In a ones complement system, the ones complement of a number n is -n. See also twos complement.
online. (1.) Being controlled directly by or directly communicating with the computer. Contrast with offline. (2.) Pertaining to the operation of a functional unit when under the direct control of a computer.
op code. See operation code.
opaque. See opaque data type.
opaque data structure. A data structure used internally by one functional unit of code but exported for limited external use in another functional unit of code. The external uses must avoid accessing the structure's components or making assumptions about its constitution.
opaque data type. In XDR, bytes of a fixed size that are not interpreted as they pass through the data streams between computers.
opaque structure. A data item or data type whose structure is hidden from the code that is handling it.
open. To make a file available to a program for processing. Contrast with close.
Open Systems Interconnection (OSI). (1.) The interconnection of open systems in accordance with specific ISO standards. (2.) The use of standardized procedures to enable the interconnection of data processing systems.
operand. (1.) An instruction field that represents data (or the location of data) to be manipulated or operated upon. Not all instructions require an operand field. (2.) An identifier, constant, or expression that is grouped with an operator. (3.) An entity on which an operation is performed. (4.) Information entered with a command name that defines the data on which a command processor operates and that controls the running of the command processor.
operating system (OS). A set of programs that control how the system works. Controls the running of programs and provides such services as resource allocation, scheduling, input and output control, and data management.
operation. (1.) A specific action (such as add, multiply, or shift) that the computer performs when requested. (2.) In NCS, a procedure through which an object is accessed or manipulated. An operation is defined syntactically by its name and its parameters but not by its implementation. (3.) In Ada language, an operation is an elementary action associated with one or more types. It is either implicitly declared by the declaration of the type, or it is a subprogram that has a parameter or result of the type.
operation code (op code). A numeric code that tells the processor which operation to perform.
operation logging. In the SOM Replication Framework, a technique for maintaining consistency among replicasof a replicated object, whereby the execution of a method that updates the object is repeated at the site of each replica.
operator. (1.) A symbol (such as +, -, or *) that represents an operation (in this case, addition, subtraction, multiplication). (2.) A person who operates a device. (3.) In Ada language, an operator is an operation which has one or two operands. A unary operator is written before an operand; a binary operator is written between two operands. This notation is a special kind of function call. An operator can be declared as a function. Many operators are implicitly declared by the declaration of a type (for example, most type declarations imply the declaration of the equality operator for values of the type).
operator function. An overloaded C++ operator that is either a member of a class or takes at least one argument that is a class type or a reference to a class type.
optimization. The process of achieving improved run-time performance or reduced code size of an application. Optimization can be performed by a compiler, by a preprocessor, or through hand-tuning of source code.
optimize. To improve the speed of a program or to reduce the use of storage during processing.
optimized unit. An Ada-language compilation unit that has been processed by one or more of the compiler's optimizing phases. Some source-level information is unavailable to the debugger when it examines the unit. You can use an optimized unit in the same contexts as the corresponding unoptimized unit. Optimized and unoptimized units can be mixed within an Ada program.
option. (1.) An item of either hardware or software that may be purchased in addition to the basic system. An option can include cables, an adapter, a warranty, and other items. (2.) A specification in a statement that can influence the running of the statement. (3.) An installable unit of a software package. Software product options are separately installable units that can operate independently from other options of that software package.
option button. In Common Desktop Environment, a diamond-shaped button that allows you to select from a number of options.
optional facilities. In X.25 communications, facilities that may or may not be offered by the network provider to which customers choose whether or not to subscribe. See also closed user group, fast select, reverse charging, and throughput-class negotiation.
optional software. Also referred to as optional software products. Software that is not automatically installed on your system when you install the Base Operating System (BOS). Optional software can be products packaged and sold with BOS. Optional software can also be separately purchased software products that are specially ordered and not sold as part of BOS. In either case, BOS must be installed on your system before you can install optional software.
ORB (object request broker). In SOM, a CORBA term designating the means by which objects transparently make requests (that is, invoke methods) and receive responses from objects, whether they are local or remote. With SOMobjects Developer Toolkit and Runtimes, this functionality is implemented in the DSOM Framework. Thus, the DSOM (Distributed SOM) system is an ORB. See also BOA (basic object adapter) class and SOMOA (SOM object adapter) class.
ordinal number. One of the counting numbers, used to indicate position.
ordinal type. A type in which members can be counted to indicate position.
ORed. Having the logical ORoperation performed.
organization. Data that associates a named set of users who can be granted common access rights that are usually associated with administrative policy. Also, the third field of a subject identifier.
orphaned files. Files that cannot be reached by the fsck command.
orthographic projection. A representation in which the lines of a projection are parallel. Orthographic projections lack perspective foreshortening and its accompanying sense of depth realism. Because they are simple to draw, orthographic projections are often used by draftsmen. See also perspective projection.
OS. See operating system.
OS/2. Operating System/2.
OSF. Open Software Foundation.
OSI. See Open Systems Interconnection.
OSPF. Open Shortest Path First routing protocol.
OSS. OSI Session Service.
OU. Organizational Unit.
outgoing call. In X.25 communications, a call being made to another data terminal equipment (DTE).
output. (1.) The result of processing data. (2.) Pertaining to a functional unit or channel involved in an output process, or to the data or involved in such a process. (3.) Data transferred from storage to an output device. (4.) In Pascal, a predefined standard file definition.
output buffer. In Enhanced X-Windows, an area used by the Xlib library to store requests.
output device. A physical device that a computer uses to present data to a user. Synonymous with output unit.
output file. (1.) A file that a program opens so that it can write to that file. (2.) A file that contains the results of processing.
output handler. The program module responsible for distributing data generated by a process or subprocess.
output list. A list of variables from which values are written to a file or device.
output mode. An open mode in which records can be written to a file.
output redirection. The specification of an output destination other than the standard one.
output stream. Messages and other output data that an operating system or a processing program displays on output devices.
output unit. Synonym for output device.
overflow. (1.) That portion of an operation's result that exceeds the capacity of the intended unit of storage. (2.) In a register, the loss of one or more of the leftmost whole-number digits because the result of an operation exceeded the size of the register.
overflow condition. (1.) A condition that occurs when a portion of an operation's result exceeds the capacity of the intended unit of storage. (2.) A condition that occurs when the overflow line on a page has been printed or passed.
overflow line. The line specified as the last line to be printed on a page.
overlay. (1.) To write over (and therefore destroy) an existing file. (2.) A program segment that is loaded into main storage, replacing all or part of a previously loaded program segment. (3.) Repeatedly using the same areas of internal storage during different states of a program. (4.) In DPS, a collection of predefined data such as lines, shading, text, boxes, or logos that can be merged with variable data while printing on a page. (5.) In the M-Video Capture Adapter, the replacement of specified pixels of one source with pixels from another source such as memory pixels overlaid on live images.
overlay planes. One or more bit planes in a display buffer that are used to create visual data (text, graphics, and so on) that overlays the visual data in the frame buffer in a nondestructive manner. Rather than a background color, overlay planes are transparent.
overloading. (1.) In Ada language, an identifier can have several alternative meanings at a given point in the program text: this property is called overloading. For example, an overloaded enumeration literal can be an identifier that appears in the definitions of two or more enumeration types. The effective meaning of an overloaded identifier is determined by the context. Subprograms, aggregates, allocators, and string literals can also be overloaded. (2.) In C++, a capability that allows you to redefine functions and most standard C++ operators when the functions and operators are used with class types.
override. (1.) A parameter or value that replaces a previous parameter or value. (2.) To replace a parameter or value. (3.) In SOM, the technique by which a class replaces (redefines) the implementation of a method that it inherits from one of its parent classes. An overriding method can elect to call the parent class's method procedure as part of its own implementation. (Such a call is known as a parent method call.)
overscan. A characteristic of display monitors where a number of lines and horizontal pixels delivered to the monitor exceed the visible display space of the screen.
overstriking. A method of generating special characters by typing one character and then, without moving the print head to the next character position, typing the second character on top of the first.
overwrite. To record into an area of storage so that the data that was previously stored there is destroyed.
overwrite mode. A form of system operation that replaces existing characters with characters typed at the keyboard.
owner. The user who has the highest level of access authority to a data object or action, as defined by the object or action; usually the creator of the object.
ownership. The creator or namer of an entity.