Support | Mainframe Dictionary | B
A glossary of terms important to IBM mainframe machines
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z misc.
If you don't find what you seek,
please let us know.
B1: B1 Trusted Computer Systems Evaluation Criteria. A US Department of Defense security rating. IBM has acquired B1 status for z/VM and z/OS.
B2C: Business to Consumer. A subdivision of e-commerce in which a business interacts with retail customers (usually by offering goods or services for sale in an online shopfront).
Bachman: At one time an IBM business partner which provided AD/Cycle and SystemView tools, including the Database Administrator for DB2, the Data Analyst process and data modeler, and the Designer CSP code generator. The partnership broke up early 1993. Early 1996 Bachman merged with Cadre Technologies to form Cayenne Software, which was purchased by Sterling Software in August 1998. Sterling was purchased by Computer Associates in February 2000.
Backbone: Generic term for a LAN or WAN – or combination of the two – which provides connectivity between subnetworks across the enterprise. The subnetworks are connected to the backbone via bridges and/or routers, and the backbone acts as a communications trunk for LAN-to-LAN traffic.
Backend: The program in the AIX operating system that sends output to a device.
Back-level: IBMspeak for a prior release of an IBM product, which may not support certain functionality in a more recent release.
Backup RACF database: A RACF database defined in the dataset name table (ICHRDSNT) that is kept current with the primary RACF database. No IPL is required to switch to the backup should the primary fail.
Balanced routing: A networking methodology where network routes are assigned in such a manner that all routes are used equally.
Balun: Generic term for a small, passive, impedance-matching device for connecting BALanced and UNbalanced cables (e.g., 3270 coax cable with twisted pairs). Often produces a small performance degradation. Used in the IBM Cabling System.
Bandwidth: A measure of how fast a network can transfer information, originally measured in Hertz (Hz), but now used for any measure of network throughput. The more precise definition: frequency range within a radiation band required to transmit a particular signal. Measures the difference between the highest and lowest signal frequencies in millions of cycles per second.
BARC: An acronym for before, after, removal, and commit. An obsolete term for a configuration program.
Base Control Program: The core MVS, OS/390 or z/OS operating system, not including components such as JESx, ISPF, TSO/E.
BASE disk: The z/VM virtual disk that contains the text decks and macro-instructions for VTAM, NetView, and VM/SNA console support.
Batch: An accumulation of data brought together for processing or transmission, usually unattended. Less formally, the processing of such data, as opposed to on-line processing where a user is present to respond interactively.
BatchPipes: z/OS software product that began life as BatchPipes/MVS, announced April 1994. After a second release in September 1995, it was replaced March 1997 by SmartBatch for OS/390, which includes BatchPipes functionality plus some BMC software. Then, in April 2000, SmartBatch was withdrawn, and a few days later, Version 2 of BatchPipes for OS/390 was announced. Currently, BatchPipes uses the Coupling Facility to pipe data between jobs running on different systems in a Parallel Sysplex. Includes the BatchPipeWorks component.
Baud: Generic term in asynchronous transmission for the number of frequency changes per second, most commonly used as the unit of speed in communications systems. More widely, but not strictly accurately, baud is used to mean bits per second, which gives the mindlessly pedantic the opportunity to congratulate themselves on how much more they know about technology than the poor benighted individuals who use the word in this way.
BCC: Block-Check Character. In redundancy checking, a character that is transmitted by the sender after each message block to determine whether all the bits transmitted have been received.
BCD: Binary-Coded Decimal. A binary-coded notation in which each of the decimal digits is represented by a binary numeral. This differs from the pure binary notation, where the entire number is represented as a single binary numeral.
BDOS: Basic Disk Operating System. The core part of a simple operating system (e.g., PC-DOS). BDOS uses the BIOS to interface programs with the hardware. BDOS is by its nature machine-independent.
BDT: Bulk Data Transfer. z/OS product for transferring datasets from one system in an SNA network to another. Data is transferred directly without having to go through an intermediate JES spool file.
BDU: Basic Device Unit.
Beaconing: The repeated transmission of a frame sent by an adapter to indicate a serious ring problem, such as a broken line or power failure. The transmission will continue until the error is corrected.
Beamer: US name for someone who works for IBM (I-BeaMer – get it?). Fell into disuse after the general public started using the term to refer to any BMW automobile.
Benchmark: An agreed workload used as a standard against which to compare the performance of different hardware/software. For a benchmark to be useful it needs to be a public standard. IBM, naturally, has its own proprietary (and hence farcical) standards, the best known of which is RAMP-C. Other benchmarks frequently cited for IBM machines include LINPAK, Gibson Mix, ET-1, Debit-Credit, Dhrystone, RPMark, and the TPC family.
Benchmarking: Although it can mean to benchmark (see benchmark), more commonly it refers to the practice of measuring an organization’s performance against best practices, as determined by a consulting or research firm.
BEST: Build Enterprise Systems Today. Long forgotten IBM marketing program based on the idea of a customer-solution objectives plan. You pay for everything, not separately for the bits – what IBM calls a bottom-line bid. The marketing/sales people get paid on whether they can shift the plan, not the traditional product-based commission. IBM used it as a way of moving users onto strategic products as early as possible. BEST was part of IBM’s plan to develop out of box-shifting and into the systems integration market. From the user point of view BEST could be a good deal.
Best practices: Consulting and research firms try and determine what works best for a given business process as practiced by organizations who do the best job at it.
Beta: Software undergoes beta testing shortly before it’s released, to determine applicability and effectiveness and aid in final debugging. In traditional IBMspeak it is often referred to as an EEP. See Alpha2.
Big Blue Zoo: The IBM Laboratories in Rochester, Minnesota.
Big iron: Industryspeak for large, expensive, ultra-fast computers. These include conventional commercial mainframes, of which IBM is king, and other number crunching supercomputers such as Crays. See Heavy metal, Dinosaur1.
Binary compatibility: Indicates that a program will run, without recompiling from source code, in a new hardware/software environment, just as it did on the old. For example, 64-bit applications produced using AIX1 Version 4 will not execute on AIX Version 5 unless they are recompiled.
BIND1: An SNA request to activate a session between two logical units.
BIND2: The message that’s sent from one LU to another to request the establishment of a session. Under LU6.2, BINDs are negotiated by the two LUs. The LU which initiates the BIND is known as the primary LU, and the LU which receives the BIND request is known as the secondary LU.
BIND3: Berkeley Internet Name Domain. The implementation of the Domain Name System (DNS) by the University of California at Berkeley.
Biometrics: Identification through the use of any human attribute that is unique to each individual.
BIOS: Basic Input/Output System. The I/O component of a simple operating system defining the interface between the operating system and the outside world – i.e., it’s the machine-dependent part of the operating environment. Accurate imitation of the PC’s BIOS is the key to compatibility with the PC. Infringement of IBM’s copyright on its BIOS is a good way of getting yourself into court very quickly.
Bi-polar: Chip fabrication technique. In the early 1990s, bi-polar was fast but expensive, compared to CMOS – the other main technique used in IBM computers. Bi-polar was used in the large ES/9000s, but by early 1995, IBM was saying that bi-polar had had its day as the base technology in large mainframes, and that everything was coming up CMOS now. The announcement of the S/390 Parallel Enterprise Server (G4) signaled the end of bi-polar.
Bi-processor: A single box which contains two processors with different architectures – as in the MicroChannel 370-14 which contains separate mainframe and PS/2 processors.
Bit: Short for binary digit. Either of the digits 0 or 1 when used in the binary system.
Bit-mapped: A bit-mapped display is one in which the screen display (characters and/or graphics and/or image) is generated or retrieved from a full representation in memory (the bit map). The bit map contains a bit for each point of the screen display which enables high resolution screens to be displayed rapidly and accurately, but at the expense of a lot of memory (e.g., a VGA/2 screen with a resolution of 1024 x 768 pixels needs about 100KBytes of memory). Often used synonymously with APA.
BizTalk: An industry initiative headed by Microsoft to promote XML as the common data exchange language for e-commerce and application integration on the Internet. The BizTalk Framework provides guidelines on how to publish schemas (standard data structures) in XML and how to use XML messages to integrate software programs. Microsoft has also announced a product called the BizTalk Server.
BLL: Base Locator for the COBOL Linkage section.
BLOB: Binary Large OBject. A generic term for a file containing some kind of binary data (text, image, document, sound, etc). Typically BLOBs can be transferred and manipulated across a wide range of platforms. BLOBs became available in DB2 CS mid 1995.
Block: A string of data elements, such as characters, words, or physical records, that are recorded or transmitted as a unit.
Bluegrass: At one time, an internal IBM code name for a planned, low price AT-compatible PC. There were three flavors of machine: Bluegrass good, Bluegrass better, and Bluegrass best.
Blue Lightning: IBM-built 486 processor brought out mid 1993. Has optimized instruction set, 16KB internal cache, and lowered power consumption. It’s actually a 486 without a mathematical co-processor, built using high-speed CMOS. Obsolete.
BMS1: Basic Mapping Support. An interface between CICS and an application to control the movement and presentation of datastreams to and from a dumb terminal. BMS allows data to be displayed without allowing for display-dependent formatting characters. Equivalent of the IMS1 MFS.
BMS2: Broadcast Message Server. Hewlett-Packard CASE product licensed by IBM mid 1992. BMS helps integrate a variety of CASE tools into a fairly coherent environment, and was used in IBM’s SDE2 environment under AIX. See also Communique.
Boat anchor: IBMspeak for a product that is just so bad that it should be dropped over the side of a ship – like a boat anchor.
BOCE: Branch Office Customer Engineer.
BOM: Branch Office Manager.
BookManager: Publishing software for creating, formatting, reading, or browsing books and manuals. BookMaster Build modules can be used to assemble existing BookMaster files into a book, and BookMaster Read software on workstations, or AS/400, z/VM or z/OS terminals can be used to read and browse the electronic publications. Includes CD-ROM support. October 1994 enhancements included proportional fonts, color, and application initiation within books. There’s also a Library Reader Kit which allows vendors and publishers to distribute electronic books in-house without requiring a license for each user. The BookManager GUI is used by IBM as one way of delivering manuals to Web browsers (for free) on their Web site.
BookMaster: Software for developing technical publications. It’s based on SCRIPT/VS, uses GML and DCF, and runs in z/OS and z/VM environments. IBM once touted it as the documentation tool within AD/Cycle.
Boolean: An operation that follows the rules of Boolean algebra.
Borg: Part of Microsoft’s Millennium research project, which automatically makes ordinary programs distributed without any source code modification or programmer involvement.
BOSS: Business Object Server Solution. IBM initiative for managing the middleware environment, not so much at the middleware level itself but at the next level up, where it is deploying a range of OO tools, frameworks, and class libraries which overcome some of the inconsistencies between middleware object standards. See Component Broker.
Bottleneck: A software or hardware element that can degrade the performance of a device, or network.
Boundary Access Node: IBM’s variant on the RFC 1490 standard for encapsulating SNA/APPN traffic within Frame Relay. Uses the same encapsulation scheme used by bridges, which is slightly longer than the native encapsulation scheme for SNA/APPN as specified by RFC 1490/FRF.3.1.
Boundary Function: In SNA, a set of services, including Address Conversion, provided by a Subarea Node to the peripheral nodes attached to it; in HPR, the set of services provided by an HPR NN to ensure interoperability between HPR and APPN nodes.
Bps: Bits per second. In some contexts, bps means bits per second and Bps bytes per second, as in Mbps and MBps.
BQM: Business Quality Messaging.
BRADS: Business Report Application Development System. Application/Report generator, the most recent incarnation of which was announced May 1983 for the System/36. Withdrawn December 1997.
Breeze for SCLM for z/OS: Browser/e-mail-based software package notification, review and approval tool for approving the promotion of packages through the software development life cycle. See also SCLM.
Bridge: A generic term for a device (such as IBM’s 8209) for connecting two networks. The bridge functions at layer 2 of the OSI model (the data link layer), and makes interconnected LANs appear as a single LAN to attached devices. In effect the bridge sits and listens to the traffic on the two networks, and when it hears that a packet on network A is intended for network B, it makes the transfer. The two networks may be physically different; the bridge will convert the physical protocols while leaving the data formats and control data intact. As far as the end-user is concerned, all devices are connected on a single network. Compare Gateway, Router, Brouter.
BRMF: Repository Manager Batch Load Facility.
BRMS: Backup Recovery and Media Services for iSeries. Provides policy-driven backup, recovery, tape media management and archive services for tape devices. Can be used on a stand-alone iSeries 400 or in a network supporting a shared tape media inventory.
Broadband: A frequency band that is broad enough to be divided into several narrower sub-bands. This allows different kinds of transmission (such as voice, video, and data) to occur simultaneously (typically by frequency division multiplexing – see FDM). Broadband is used in the MAP standard and IBM’s DAE, and was used as the carrier technology in the defunct PC Network. cf. Baseband.
Broadband LAN: A local area network (LAN) that consists of more than one channel, in which data is encoded, multiplexed, and transmitted with modulation of carriers.
Broadband Network Services: IBM high-speed networking architecture announced July 1993 to support ATM2 and other broadband services. Includes control and management functions, support for open interfaces, managed pipes for user traffic, and support for ATM cells and variable length packets. Implemented in a range of chip-level technologies.
Brouter: Generic term for a hybrid bridge and router. Typically it functions as a router at layer 3 of the OSI model and then steps down to layer 2 if it can’t find the network information it needs to function at layer 3.
BrowseMaster: z/VM and z/OS product enabling the user to view and manipulate (fairly limited) documents to be printed on a page printer. Part of the VM SolutionPac publishing system. GDDM is a pre-requisite. Still available.
Browser: Generic term for software which allows users to meander around a collection of information. Usually used to refer to Web browsers (such as Netscape or IE1) which enable people to waste inordinate amounts of time failing to find any useful information on the Internet (assuming they can get a reliable Internet connection in the first place).
Browser plug-in: A client application, usually not Java-based, that can be dynamically downloaded from a Web server when invoked from a Web browser, and then executed on the client. A browser plug-in is required to run IE1-centric ActiveX software with Netscape.
BRS: Business Recovery Services. IBM disaster recovery service in the USA. Set up early 1989 to provide backup for users of mainframes, AS/400s, and System/3xs. Now a part of IBM Global Services known as Business Continuity and Recovery Services.
BSC: Binary Synchronous Communications. A character-oriented synchronous link communications protocol evolved from the old async (start-stop) protocol. Originated by IBM in 1964. Synchronization of the sending and receiving stations is established before the message is sent, which allows faster block-mode data transmission and fewer data errors than start-stop. Speed comes from the lower ratio of checking bits to data bits (i.e., it’s not carrying as much junk around as async). Widely used, but superseded within IBM’s mainstream products by SDLC1/SNA protocols. Also known as Bisync, Bisynch and Bisynchronous.
BSCA: Binary Synchronous Communications Adapter.
BSCEL: Binary Synchronous Communications Equivalence Link.
BSD: Berkeley Software Distribution. A version of the Unix operating system.
BSP: Business Systems Planning. IBM methodology (announced in 1970) for analyzing the structure/clustering of business activities. Uses the top-down approach. An enhanced version of BSP was used as the basic modeling technique for IBM’s ill-fated Repository.
BTAM: Basic Telecommunications Access Method. The first access method common to the predecessors of VSE/ESA and z/OS: provides low-level services for reading from and writing to TP devices. Problems with the complexity of BTAM led to the evolution of TP monitors such as CICS. BTAM was largely superseded by access methods, such as VTAM, which implement the SNA procedures (BTAM does not support SNA devices). Withdrawn for VSE/ESA June 2000 and z/OS March 2000. Support ends March 2002 for both platforms.
BTAM-ES: BTAM Extended Support. BTAM for VSE. Based on the BTAM component of DOS/VS Release 34. Announced January 1979, withdrawn June 2000 with end of support March 2002.
BTP1: Basic Terminal Processor.
Bubblegum: IBMspeak for the IBM Boeblingen Lab in Germany at which much of the development of VSE/ESA and mid-range mainframes happened.
Buckets-based: An optional extension to the malloc subsystem, the default AIX1 memory allocator. Intended to speed up applications that issue large numbers of small allocation requests. A buckets-based approach satisfies all small memory requests with pre-divided chunks of memory of a uniform fixed size. Announced April 2001 in AIX 5L Version 5.1.
Buffer: A relatively small amount of memory, directly available to the CPU, which momentarily holds either instructions or other information. Not to be confused with memory cache. Buffers are used to overcome factors that affect direct access of instructions or data to the CPU, such as speed differences, interface delays, and other variations between a device and the CPU.
Buffer pool: Main memory holding data being read or written.
Build-to-Plan: One of several approaches to order fulfillment that IBM uses. This one sees them preassembling hardware and software products based on forecasts of exactly what configurations customers will order. cf. Build-to-Order.
BUNCH: IBM and the BUNCH was the industry term for the main players in the computer industry during the heady days of the 1960s and 1970s. The BUNCH, who had emerged from the Seven Dwarves, were Burroughs, Univac, NCR, Control Data, and Honeywell. However, Honeywell was bought out by Bull, Univac merged with Sperry to form Sperry/Univac, which in 1984 merged with Burroughs to form Unisys, and in 1991 AT&T absorbed NCR. See Seven Dwarves, Dinosaur mating.
Bundling: The practice of selling hardware and/or software in packages, so that users get (and pay for) all sorts of things they may not want. The attraction to the vendor is that the unit of purchase is large. IBM voluntarily abandoned such practices in the US (see Consent decree) but Microsoft now gets accused of similar activities.
Burst: Data communication terminology for a data sequence that is counted as a single unit based on a specific criterion or measure.
Bus and tag: The physical cabling system for attaching high-speed devices to mainframe processor channels. Uses a synchronous byte-oriented (9 bits in parallel) protocol in which bus wires carry data, and tag wires carry control information. Unfortunately, if the distance or baud rate is too great, the parallel electrical signals can get skewed – i.e., they arrive at different times – limiting both the distance of the connection (to about 122 meters) and the bandwidth (about 4.5MB/sec). Bulky and clumsy, traditional copper bus and tag were replaced by ESCON fiber optics throughout the IBM mainframe range. See Boa2.
Business Process Modeler: OS/2 CASE1 tool for modeling workflow. Built on IBM’s Line of Visibility Enterprise Modeling (LOVEM) methodology and integrated with FlowMark. Announced February 1996 and withdrawn June 1998.
Business to Business: Buying and selling between organizations, as opposed to Retailing, where Consumers are involved.
Bus master: A device that controls data transfers between itself and a subordinate.
Busmaster: PS/2 LAN adapter cards providing co-processor support for machines acting as LAN servers. The Busmaster takes over the MCA or EISA bus and off-loads processing work from the main processor – usually by transferring data directly into memory without any involvement by the processor. IBM’s product, the Token Ring Network 16/4 Busmaster Server Adapter/A was announced December 1990 and withdrawn June 1993.
BYPASS2000: AS/400 software that assists the conversion of two-digit dates in RPG and COBOL programs. BYPASS2000 analyses an application’s programs and files, stores information, traces memory use of data, handles overlays, rewrites source programs, generates file-conversion programs, and assists data-simulation tests. Withdrawn May 2000. See Y2K.
Byte: A string of 8 bits that represents one EBCDIC character. The IBM mainframe architecture is organized around the concept of the byte.