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backbone: A set of nodes and their interconnecting links that form a central, high-speed network interconnecting other, typically lower-speed, networks or client nodes.
background color: In the GDDM® function, the first color of the display medium; for example, black on a display or white on a printer. See also neutral color.
back out: To remove changes from a physical file member in the inverse order from which the changes were originally made.
backout: An operation that reverses all the changes made during the current unit of recovery or unit of work. After the operation is complete, a new unit of recovery or unit of work begins. See also commit.
backout recovery: The process of returning a file to a particular point by removing journaled changes to the file.
backplane: A hardware part that has (in one or more planes) logic paths, low-voltage distribution paths, and grounding paths of a section of a machine.
back up: To save information or objects on a system, usually to tape or diskette, for safekeeping.
backup: (1) Pertaining to an alternative copy used as a substitute if the original is lost or destroyed, such as a backup log.; (2) A tape, diskette, or save file containing saved objects.; (3) The process of copying a file, directory, file system, or other data onto a tape, disk, or other media as insurance against data loss or corruption. When a user backs up a directory or filesystem, the backup procedure preserves the directory structure. See also restore.
backup control group: In Backup Recovery and Media Services, a group of libraries, system keywords, and lists that share common backup characteristics. The default values for a backup control group are defined in the backup policy and can be used or overridden by each backup control group.
backup focal point: A focal point that provides management services support for a particular category for a node in the event of a communications failure with the primary focal point. Both assigned focal points (explicit and implicit) and default focal points can have backup counterparts. See also primary focal point.
backup history: In Backup Recovery and Media Services, a report of what has been backed up with a BRMS backup policy. A backup history contains information about each item such as what type of object it is, the date and time it was saved, and when the saved item expires. Synonymous with media information report.
backup list: (1) In the Operational Assistant function, a list of libraries or folders to be saved on a regular basis, such as daily or weekly.; (2) In Backup Recovery and Media Services, a group of objects or folders that are grouped together for processing in a backup control group. Each list is assigned a unique list name.
backup node: A cluster node on which there is a secondary copy of a cluster resource. The copy is kept current through replication.
backup policy: In Backup Recovery and Media Services, a set of controls that are used to track information about the items that are being backed up, when they are being backed up, and where they are being backed up. Backup policy is a combination of the concepts of control group and media policy.
Backup Recovery and Media Services (BRMS): An IBM® licensed program that provides user-modifiable backup, archive, recovery, and media management functions and policies.
backup system: In iSeries™ Navigator, a server that replaces a central system when the central system requires maintenance or upgrades.
bandwidth: The capacity of a communications line, normally expressed in bits per second (bps).
bar chart: A chart consisting of several bars of equal width. The value of the dependent variable is indicated by the height of each bar.
bar code: A pattern of bars of various widths containing data to be interpreted by a scanning device.
bar graph: In Performance Tools, a graph consisting of several bars of equal width. The value of the dependent variable is indicated by the height of each bar.
base: The numbering system in which an arithmetic value is represented.
base aggregate table: In SQL replication, a type of replication target table that contains data that is aggregated from a replication source table.
baseband: A frequency band that uses the complete bandwidth of a transmission and requires all stations in the network to participate in every transmission.
base class: See parent class.
base number: The part of a self-check field from which the check digit is calculated.
base pool: A storage area that contains all unassigned main storage on the system and whose minimum size is specified in the system value QBASPOOL. The system-recognized identifier is *BASE.
base project: In VisualAge® RPG, a collection of files that make up a VRPG component.
BASIC (beginner's all-purpose symbolic instruction code): A high-level programming language with a small number of statements and a simple syntax. BASIC is designed to be easily learned and used and is widely used for interactive applications on microcomputers.
basic assistance level: The type of displays that provides the most assistance. Basic assistance level supports the more common user and operator tasks, and does not use computer terminology.
basic assurance test (BAT): An automatic testing of a machine when the power is switched on.
basic character: Frequently used double-byte character that is stored in the hardware of a DBCS-capable work station. The number of double-byte characters that are stored in the work station varies with the language supported and the storage size of the work station. A DBCS-capable work station can display or print basic characters without using the extended character processing function of the operating system. See also extended character processing, extended character.
basic conversation: In APPC, a conversation between two programs in which the sending program must construct generalized data stream (GDS) records for the receiving program.
basic data exchange: A file format for exchanging data on diskettes or tape between systems or devices.
basic disk pool: One or more storage units that are defined from the disk units or disk-unit subsystems that make up addressable disk storage. Disk pools (which are also known as auxiliary storage pools ) provide a means of placing certain objects on specific disk units to limit the impact of disk-media failures and to reduce recovery time. A basic disk pool contains both objects and the libraries or directories that contain the objects. Attributes such as authorization, ownership, and spooled file attributes are stored in the system disk pool (also known as the system ASP).
basic DST capability: A dedicated service tools (DST) capability used by a service representative or an experienced system user that provides access to DST functions that do not access sensitive data.
Basic Encoding Rules (BER): A set of rules used to encode ASN.1 values as strings of octets.
basic information unit (BIU): In SNA, the unit of data and control information passed between the transmission and control layers. It consists of a request or response header followed by a request or response unit.
Basic Input/Output System (BIOS): The code that controls basic hardware operations, such as interactions with diskette drives, hard disk drives, and the keyboard.
basic link unit (BLU): In SNA, the unit of data and control information transmitted over a communications line by data link control.
basic mapping support (BMS): An interface between CICS® and application programs that formats input and output display data and routes multiple-page output messages without regard for control characters used by various terminals.
basic rate interface: The means of ISDN access normally used by private subscribers, providing two B-channels of 64kbits per second and one D-channel of 16kbits per second for signaling. This is often known as 2B+D.
Basic Telecommunications Access Method (BTAM): An access method that permits read and write communication with remote devices.
BAT: See basic assurance test.
batch: Pertaining to a group of jobs to be run on a computer sequentially with the same program with little or no operator action. See also interactive, interactive.
batch accumulator: In DFU, an accumulator in which subtotals for a field are stored. See also total accumulator.
batch device: Any device that can read serial input or write serial output, or both, but cannot be used to communicate interactively with the system. Examples of batch devices are printers, magnetic tape units, or diskette units.
batch file: A file containing data that is to be processed unattended.
batch job: A predefined group of processing actions submitted to the system to be performed with little or no interaction between the user and the system. See also interactive job.
batch mode: In query management, the query mode associated with a query instance that does not allow users to interact with the query commands while a procedure is running.
batch processing: A method of running a program or a series of programs in which one or more records (a batch) are processed with little or no action from the user or operator. See also interactive processing.
batch shell: In CICS, a shell started to handle CICS interval control timer requests. The batch shell is transparent to the user; each user's program runs under its own user shell.
batch subsystem: A part of main storage where batch jobs are processed.
battery power unit: A source of electrical power that can be used when the normal utility power fails.
BCB: See block control byte.
BCC: See block-check character.
B-channel: See bearer channel.
beaconing: Pertaining to an adapter in a token-ring network that repeatedly sends a frame (beacon message) when it is not receiving a normal signal because of serious error, such as a line break or power failure. The message frame repeats until the error is corrected or bypassed. See also beacon message.
beacon message: A message frame sent repeatedly by an adapter indicating a serious network problem, such as a broken cable. See also beaconing.
bean: A definition or instance of a JavaBeans™ component. See also JavaBeans.
bearer channel (B-channel): In ISDN, a duplex channel for transmitting data or digital voice between the terminal and the network. The B-channel operates at 64 kilobits per second. See also delta channel.
BEC: See bus extension card.
BED card: See bus extension driver card.
before-image: The contents of a record in a physical file before the data is changed by a write, an update, or a delete operation.
beginner's all-purpose symbolic instruction code: See BASIC.
beginning attribute character: For a display file, the character that precedes the first position in a field and that defines how the data in the field is displayed.
beginning-of-tape marker (BOT marker): A reflective material placed on a magnetic tape to indicate where the recording area starts.
BER: See Basic Encoding Rules.
BER card: See bus extension receiver card.
BEST/1 for iSeries: The capacity planner for a system. The BEST/1 for iSeries capacity planner is a function of the IBM Performance Tools licensed program.
best-effort service: In QoS, the type of service that by default is assigned to all traffic unless a network policy specifies otherwise. This traffic is not given special forwarding treatment.
best-fit conversion: See linguistic conversion.
bezel: A rim or surrounding part to keep another part stationary.
BGU: See Business Graphics Utility.
bidder: An SNA LU-LU half-session that is defined as requesting and receiving permission from another LU-LU half-session to begin a bracket at the start of a session. See also first speaker.
bidirectional language: A language such as Arabic and Hebrew whose general flow of text proceeds horizontally from right to left, but numbers, English, and other left-to-right language text are written from left to right.
big endian (MSB): A format for storage or transmission of binary data in which the most significant bit (or byte) is placed first. See also little endian.
bin: An enclosure on a printer that contains source or destination media, including paper, foils, labels, card stock, or microfilm.
binary: (1) Pertaining to a selection, choice, or condition that has two possible values.; (2) In DB2® UDB for iSeries, pertaining to a data type indicating that the data is a binary number with a precision of 15 (halfword) or 31 (fullword) bits.; (3) Pertaining to a system of numbers with a base of two . The binary digits are 0 and 1.
binary digit (bit): The smallest unit of computer information, which has two possible states that are represented by the binary digits 0 or 1.
binary file: A file that contains codes that are not part of the ASCII character set. Binary files can utilize all 256 possible values for each byte in the file.
binary floating-point number: The conceptual form of a numeric value that contains a significand and a signed exponent. The number's numeric value is the signed product of the number's significand and 2 raised to the power of the number's exponent.
binary format: Representation of a decimal value in which each field must be 2 or 4 bytes long. The sign (+ or -) is in the far left bit of the field, and the number value is in the remaining bits of the field. Positive numbers have a 0 in the sign bit and are in true form. Negative numbers have a 1 in the sign bit and are in twos complement form.
binary integer: A basic data type that can be further classified as small integer or large integer.
binary item: Numeric data that is represented internally as a number in the base 2 numbering system; internally, each bit of the item is a binary number with the sign as the far left bit.
binary large object: A block of bytes of data (for example, the body of a message) that has no discernible meaning, but is treated as one solid entity that cannot be interpreted.
binary operator: A symbol representing an operation to be performed on two data items, arrays, or expressions. See also unary operator.
binary stream: In the C language, a sequence of characters that corresponds on a one-to-one basis with the characters in the file. No character translation is performed on binary streams.
binary string: In REXX, a literal string expressed using a binary (base 2) representation of a value. The binary representation is a sequence of zero or more binary digits (the characters 0 or 1) enclosed in quotation marks and followed by the character b.
binary synchronous communication (BSC): A data communications line protocol that uses a standard set of transmission control characters and control character sequences to send binary-coded data over a communications line.
binary synchronous communications equivalence link support (BSCEL support): The intersystem communications function (ICF) support on the iSeries system that provides binary synchronous communications with other computers using BSC protocols.
bind: (1) To create a program, which can be run, by combining one or more modules created by an Integrated Language Environment® (ILE) compiler.; (2) To convert the output from the SQL compiler or DMBS precompiler to a usable control structure, such as an access plan, application plan, or package. During the bind process, access paths to the data are selected and some authorization checking is performed.
BIND command: In SNA, a command used to start a session between two logical units, and to define the characteristics of that session. See also UNBIND command.
binder: The system component that creates a bound program by packaging Integrated Language Environment (ILE) modules and resolving symbols passed between those modules.
binder language: A small set of commands (STRPGMEXP, EXPORT, and ENDPGMEXP) that defines the external interface (signature) for a service program. These commands cannot be run alone and are of the source type BND.
binding: The process of creating a program by packaging Integrated Language Environment (ILE) modules and resolving symbols passed between those modules.
binding directory: A list of names of modules and service programs that may be needed when creating an ILE program or service program. A binding directory is not a repository of the modules and service programs. Instead, it allows them to be referred to by name and type.
BIOS: See Basic Input/Output System.
bit: See binary digit.
bit data: Data with character type CHAR or VARCHAR that is not associated with a coded character set and therefore is never converted.
bitmap: A coded representation in which each bit, or group of bits, represents or corresponds to an item; for example, a configuration of bits in main storage in which each bit indicates whether a peripheral device or a storage block is available or in which each group of bits corresponds to one pixel of a display image.
bit mask: A pattern of bits designed to be logically compared to an existing bit value. The mask pattern allows only certain desired parts of the existing bit value to appear in the result of the comparison.
bits per inch (bpi): The density, measured in number of bits per inch, at which information can be stored on magnetic tape.
bits per second (bps): In serial transmission, the instantaneous bit speed with which a device or channel transmits a character.
bit string: A series of bits consisting of the values 0 and 1.
BIU: See basic information unit.
blank after: In RPG, an output specification option that changes the contents of a field so that it contains either zeros (if it is a numeric field) or blanks (if it is a character field) after that field is written to the output record.
block: A sequence of text, commands, or records that are read, written, or processed as a unit.
block-check character (BCC): The BSC transmission control character that is used to determine if all of the bits that were sent were also received.
block control byte (BCB): In a multileaving telecommunications access method, a control character used for transmission block status and sequence count.
block copy: In SEU, to copy two or more adjoining source records from one part of a source member to another part, or from one source member to another.
block delete: In SEU, to delete two or more adjoining source records from a source member.
block edit function: In AFP™ Utilities, a function that moves, copies, or removes all elements defined in a specified scope on the image area at one time.
blocked signal: In POSIX, a condition that prevents a signal-handling action associated with a signal from being performed. See also unblocked signal.
block exclude: In SEU, to exclude two or more adjoining records from the Edit or Browse display.
blocking factor: The number of records in a block. A blocking factor is calculated by dividing the size of the block by the size of the record.
block move: In SEU, to move two or more adjoining source records from one part of a source member to another part, or from one source member to another.
block overlay: In SEU, to overlay two or more adjoining records with other records defined by the Copy or Move line command.
block statement: In the C or C++ languages, a group of data definitions, declarations, and statements appearing between a left brace and a right brace that are processed as a unit. The block statement is considered to be a single, C-language statement. In Ada language, a block statement is a single statement that may contain a sequence of statements. It may also include a declarative part, and exception handlers; their effects are local to the block statement.
BLU: See basic link unit.
BMS: See basic mapping support.
Boolean data: In COBOL, a category of data items that are limited to a value of 1 or 0.
Boolean literal: In COBOL, a literal composed of a Boolean character enclosed in double quotation marks and preceded by a B; for example, B "1" .
Boolean operator: In REXX, an operator each of whose operands and whose result take one of two values (0 or 1).
BOOTP: See Bootstrap Protocol.
Bootstrap Protocol (BOOTP): A protocol that allows a client to find both its Internet Protocol (IP) address and the name of a file from a server on the network.
border: A public address that forms a border between a trusted and an untrusted network. It describes the IP address as an actual interface on the system. The system needs to know the "type" of address you are defining. For example, your PCs IP address is trusted, but your server's public IP address is border.
border system: A system that exists within a trusted system but communicates between trusted and untrusted systems. A border system prevents security from being compromised.
both field: A field that can be used for either input data or output data.
BOT marker: See beginning-of-tape marker.
bottleneck: A place in the system where contention for a resource is affecting performance.
bottom margin: On a page, the space between the body or the running footing, if any, and the bottom edge of the page.
boundary violation: In COBOL, an attempt to write beyond the externally defined boundaries of a sequential file.
bound program: An i5/OS™ object that combines one or more modules created by an Integrated Language Environment (ILE) compiler.
box: A line enclosure that forms a rectangle around text or a table.
bpi: See bits per inch.
bps: See bits per second.
bracket: In SNA, one or more chains of request units and their responses, representing a complete transaction, exchanged between two session partners.
bracketed DBCS: A character string in which each character is represented by 2 bytes. The character string starts with a shift-out (SO) character and ends with a shift-in (SI) character.
bracket protocol: In SNA, a data flow control protocol in which exchanges between two session partners are achieved through the use of brackets, with one partner designated at session activation as the first speaker and the other as the bidder. The bracket protocol involves bracket initiation and termination rules.
branch instruction: An instruction that changes the sequence of instructions processed in a computer program. The sequence of instructions continues at the address specified in the branch instruction.
break delivery: The method of delivering messages to a message queue in which the job associated with that message queue is interrupted as soon as the message arrives.
break field: In AFP Utilities, a field that causes a page break. When the Print Format Utility encounters a record with a value that is not equal to that of the previous record, a page break occurs.
breakpoint: A place in a program (specified by a command or a condition) where the system stops the processing of that program and gives control to the display station user or to a specified program.
breakpoint program: For a batch job, a user program that can be called when a breakpoint is specified.
British thermal unit (Btu): The amount of heat required to raise a pound of water by 1 degree Fahrenheit.
British thermal unit per hour (Btu/hr): An English unit of measure for heat produced in one hour.
BRMS: See Backup Recovery and Media Services.
broadband: A communication channel that uses a wide frequency range divided into narrower bands that can be made available to different users for the simultaneous transmission of different signals (such as voice, video, and data). A broadband is capable of higher-speed data transmission than a voice-grade channel.
broadcast: The simultaneous transmission of the same data to all nodes connected to a network. See also multicast.
broadcast message: A message sent to all workstations.
browse: In message queuing, to use the MQGET call to copy a message without removing it from the queue.
browse cursor: In message queuing, an indicator used when browsing a queue to identify the message that is next in sequence.
BSC: See binary synchronous communication.
BSC 3270 device emulation: A function of the operating system that allows a server to appear to a BSC host system as a 3274 Control Unit.
BSCEL support: See binary synchronous communications equivalence link support.
BTAM: See Basic Telecommunications Access Method.
Btu: See British thermal unit.
Btu/hr: See British thermal unit per hour.
buffer: An area of storage that compensates for the different speeds of data flow or timings of events by temporarily holding a block of data that is waiting to be processed or written to an I/O device.
build: In the Application Development Manager feature of the Application Development ToolSet licensed program, the procedure that processes a part into a program.
build process: In the Application Development Manager feature of the Application Development ToolSet licensed program, the procedure that determines which parts of an application have changed, and based on the relationship between those parts, compiles them in the correct order.
build report: In the Application Development Manager feature of the Application Development ToolSet licensed program, a report that describes the results of the build process. This report can be printed or viewed on a display.
built-in function: (1) In C and CL, a predefined function, such as a commonly used arithmetic function or a function necessary to high-level language compilers (for example, a function for manipulating character strings or converting data). It is automatically called by a built-in function reference.; (2) In REXX, a function that is supplied by a language. These functions, defined as part of the REXX language, include character manipulation, conversion, and information functions.
built-in function reference: In CL, a built-in function name, having an optional, and possibly empty, argument list that holds the value returned by the built-in function.
bundle: A group of journal entries that are deposited together by the system.
burst: In AFP support, to separate continuous-forms paper into separate sheets.
bus: One or more conductors used for transmitting signals or power.
bus expansion: An expansion unit that attaches to a system unit for the purpose of increasing the number of buses on the system and which allows for additional I/O processor cards to be attached.
bus extension card (BEC): The bus extension driver card or the bus extension receiver card.
bus extension driver card (BED card): The card, connected by a cable to a bus extension receiver (BER) card, that is used to route data from one card enclosure to another card enclosure. The direction of data can be from the processing unit to an input/output processor in one of the card enclosures, or from an input/output processor in one of the card enclosures to the processing unit. See also bus extension receiver card.
bus extension receiver card (BER card): The card, connected by a cable to a bus extension driver (BED) card, that is used to route data from one card enclosure to another card enclosure. The direction of data can be from the processing unit to an input/output processor in one of the card enclosures, or from an input/output processor in one of the card enclosures to the processing unit. See also bus extension driver card.
Business Graphics Utility (BGU): The IBM licensed program that can be used to design, plot, display, and print business charts.
business intelligence: The consolidation and analysis of data collected in the day-to-day operation of a business, which is then used as a basis for better business decisions and competitive advantage.
business management: In System Manager, the discipline that encompasses inventory management, security management, financial administration, business planning, and management services for all enterprise-wide information systems.
bus-level partitioning: The dedicated allocation of an entire bus and all accompanying resources (input/output processors and input/output devices) to a particular logical partition. See also IOP-level partitioning.
button: A mechanism on a pointing device, such as a mouse, used to request or start an action.
bypass plug: Allows power to flow through an unused outlet in the power control compartment.
byte: A string that represents a character and usually consists of eight binary digits that are treated as a unit. A byte is the smallest unit of storage that can be addressed directly.
bytecode: Machine-independent code generated by the Java™ compiler and executed by the Java interpreter. (Sun)