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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.
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G2G: Green-to-GUI. A cute term for user interface rejuvenation.
Gallium arsenide: Semiconductor fabrication technique which does away with silicon as the substrate for chip manufacture and uses gallium arsenide (GaA) instead. However, fabrication is expensive, compared with CMOS, and chip yields are low. This has limited its use to supercomputer and military applications. See Silicon/germanium.
Garbage collection: A software technique to free up previously-used, but currently unneeded, storage, typically memory within the allocated address space for a program/application/system. Because the result may be a lot of little pieces of non-contiguous memory, some garbage collection algorithms also include a compaction of the memory that is still in use. Obviously, garbage collection is only required for software that does not automatically release memory along the way, when it first stops being used, though compaction would still be of benefit.
Gateway: Equipment on a network that enables a terminal on one network to communicate with a terminal on another (incompatible) network. The gateway may convert data formats and protocols as well as physical formats and protocols. Most widely used in the IBM world to connect LANs and SNA networks, where the gateway (often a card plus some software in a PC) converts the NetBIOS protocols into SNA protocols. PADs and protocol converters are typical gateways.
GDG: Generation Data Group. Collection of (z/OS non-VSAM) datasets (see GDS2) all with the same logical name (GDG Base Entry); the individual datasets are uniquely identified by the generation number which is stored as part of the dataset name. The datasets can be referenced either by the explicit generation number or the relative generation number. GDGs are useful where datasets are cycled – standard JCL can be used without having to change the dataset names for each run.
GDLC: Generic/General Data Link Control Interface. Defines a common interface with the same set of commands for multiple DLCs. DLCs that conform to the GDLC interface include Token Ring, IEEE802.3 for Ethernet, Standard Ethernet, SDLC1, QLLC and FDDI.
GDMO: Guidance for Definition of Managed Objects. An ISO standard for object-oriented systems.
GDPS: Geographically Dispersed Parallel Sysplex. A service offering of IBM Global Services that manages z/OS remote copy configuration and storage subsystems, automates Parallel Sysplex operational tasks and performs failure recovery from a single point of control. Comes in two flavors: GDPS/PPRC and GDPS/XRC.
GDPS/PPRC: Geographically Dispersed Parallel Sysplex/Peer to Peer Remote Copy. A hardware-only GDPS approach that synchronously mirrors data residing on a set of z/OS disk volumes to a remote site. cf. GDPS/XRC.
GDPS/XRC: Geographically Dispersed Parallel Sysplex/eXtended Remote Copy. A combination of hardware and z/OS software that performs an asynchronous remote copy. Unlike GDPS/PPRC, no dark fiber is required, and there is no 40km distance limit. See also GDPS.
General availability: Perhaps one of IBM’s oldest terms still in use. The time period beginning on the first scheduled day of shipment of a product to customers not involved in beta testing or other early release programs. And ending on the Withdrawal date. More precisely, the Marketing Withdrawal date, as opposed to the end of support. It is always amusing to find Withdrawal dates that are years behind end of support.
Generic character: In RACF, a special pattern-matching characters, such as the asterisk (*), known as wildcard characters in other operating systems, that are invalid in dataset names, but are used in generic profiles to specify all dataset names that match the specified pattern.
geoGPG: GEOgraphic Graphics Program Generator. AIX geographic information system (GIS) based on a network topological model. geoGPG allows automated mapping and facility management (AM/FM) applications to manage geographically located facilities, assets and events. Announced February 1991 as IBM AIX geoGPG/6000, then renamed IBM geoGPG for AIX December 1995.
geoManager: IBM geoManager Relational Database System. Provides DB2 support for GFIS in z/OS, z/VM, AIX and Windows environments, as well as Oracle support for AIX. The graphic analysis feature allows editing and update of attribute data stored in the database.
Gerstner: Lou Gerstner is the man who became Chief Executive of IBM in April 1993 (it just had to be April the 1st, didn’t it?). His background was in biscuits (leading to suggestions that he must be crackers) and charge cards. The non-computer background augured well, since he’s not carrying the burden of a lifetime’s immersion in the IBM culture.
Gibson Mix: A synthetic workload (benchmark) used by IBM to calculate the effective MIPS ratings of its large processors. Effectively it measures the average execution time of a mix of instructions.
GIF: Graphics Interchange Format. A standard for defining raster (bit-mapped) images, whose wide popularity suddenly dropped after Unisys declared that it would be asserting its intellectual property rights in it. Largely being replaced by JPEG though you still see a lot of GIFs on Web pages.
Gigabit Ethernet: A standard for Ethernet using optical fiber cable to obtain 1Gbps data transfer rates.
Giga processor: The name of the eserver pSeries in the media when it was still in the rumor stage.
GIO: Growth Incentive Option/Offer. IBM marketing program. Basically you get a whopping discount on upgrades if you commit to them early.
GIS: Geographic Information Systems. Systems which manage geographic information for map making, demography, geology, and the like. It has proved a lucrative market sector over the last 15 years, and IBM has set up a number of joint ventures to exploit it (e.g., with the University of California at Santa Barbara, UGC, the geoGPG product, and the National Center for Geographic Information and Analysis).
Glass teletype: A generic name for dumbCRTs. More strictly it’s used to mean terminals which appear to be teletypes as far as other devices are concerned, but which have a screen rather than a roll of paper as the output medium. Obsolete.
Global Financing: IBM Global Financing. The largest lender of money in the Computing world, to the tune of $20 billion to customers and another $30 billion to business partners. Operates in 40 countries. Is also behind Capacity Upgrade on Demand, financing the spare hardware until it is required.
Global Network: A division of IBM which AT&T bought in December 1998 for $5 billion cash. As part of the deal IBM outsourced a large amount of its global networking needs to AT&T, which in turn outsourced certain applications processing and data center management back to IBM.
Global Services: IBM Global Services. IBM’s consulting practice, averaging 50,000 consultants at work worldwide. Outsourcing is about 40% of the business.
GMLC: Graduated Monthly License Charge. A monthly charge for mainframe software based on the power of the processor on which the software is to run. Introduced at the beginning of 1989, superseding the flat monthly license charge (MLC). Currently available for z/VM, but not z/OS. See also GOTC, FMLC, IMLC.
Goal mode: A mode of processing within Workload Manager (WLM) where the active service policy determines system resource management. The alternative is Compatibility mode where the IEAIPSxx and IEAICSxx parmlib members determine system resource management. The z/OS Intelligent Resource Director requires that WLM be running in Goal mode.
GOCA: Graphics Object Content Architecture. Defines the structure and content of graphic image data. Includes location and content of lines, curves, drawing orders, etc. Superset of the I/O graphics standards of IPDS.
GOLC: Growth Opportunity License Charge. A monthly IBM software fee for the operating system and systems software introduced September 1999 to support the System/390 Multiprise 3000 line of small mainframes. Initially, GOLC provides a discounted price based on the size of the previous processor, then continues with a lower price that recognizes the size (small) of the Multiprise 3000. Includes both z/OS and z/VM.
Golden: Golden Common LISP. LISP learning tool and development environment for PC-DOS from Gold Hill Computers. Announced December 1985 as an IBM Program Offering. Withdrawn June 1987. Abbreviated as GCLISP and GLISP.
Golden Screwdriver: In the old days when a customer ordered the smallest mainframe in a range IBM had the option of shipping a machine with a bigger processor and more memory but with software which prevented the extra power and storage being exploited. If the customer at a later date wanted an upgrade then an engineer would arrive with his golden screwdriver and erase the code which was slowing down the machine. The result was a more powerful machine and a huge invoice for the upgrade.
Gopher: An Internet protocol, developed at the University of Minnesota, that provides a menu-driven interface for accessing files and information on other computers. The protocol was named Gopher after the Minnesota University mascot, the Golden Gopher. Few Internet sites use Gopher anymore, as HTTP-based Web sites offer more flexibility.
GOTC: Graduated One Time Charge. One time charge for IBM software introduced at the beginning of 1989. Unlike OTC, the GOTC varies according to the processor for which the software is licensed. At the beginning of 1999, OTC and GOTC options were dropped from any mainframe software product for which a monthly charge option was available. See also GMLC.
GPFS: General Parallel File System. GPFS for AIX is a shared disk file system for parallel and serial applications. GPFS for Linux is similar but for Red Hat Linux running on xSeries.
GPSI: General Purpose System for Inferencing. Expert system used in the RT PC for diagnostic services. Developed at the University of Illinois with IBM funding. Obsolete.
GPT: Generalized Path information unit Trace. A record of the flow of path information units (PIUs) between a network control program and its resources.
Granularity: Although it can refer to level of detail in almost any context, granularity is more commonly used to refer to the closeness of the incremental power steps in a manufacturer’s processor range. A highly granular range is one where you can move to a more powerful processor without having to buy one far too big for your needs. The IBM mainframe range is pretty granular today, although it hasn’t always been so in the past, and some of the PCM vendors had a fine old time filling the gaps in a non-granular (lumpy?) IBM range.
GraphicsView/2: SystemView graphics application on OS/2 EE. Provides an SAA-conformant graphical interface for displaying network configurations to help the operator interpret LAN management data. Announced September 1990. Withdrawn September 1997.
graPHIGS: Support for the ANSI PHIGS standard. Originally in stand-alone products, but now included in AIX.
Green card: The name given by system programmers for the IBM mainframe reference summary booklets, no matter what the color. Named because the original System/360 versions were green fan fold cards. At least, the size remains the same: just right for slipped into a shirt pocket. The problem, of course, is the lack of shirt pockets in much of today’s attire.
Groupware: Once a popular buzzword for software which provides support for groups of people working collaboratively on projects. IBM’s principal groupware offering is the Notes software from its Lotus subsidiary. See also Person to Person.
GTA: General Trading Architecture. IBM architecture for financial (e.g., stock exchange type) applications.
GTF: Generalized Trace Facility. An optional z/OS utility that records system events, which can be used for problem diagnosis. Events such as supervisor calls and start I/O operations are recorded. Very resource greedy (up to 20% of processor cycles) but useful for intractable system problems.
GTMOSI: General Teleprocessing Monitor for OSI. z/OS CICS teleprocessing monitor providing tools to help users write native OSI applications at layers 6 (presentation) and 7 (application). Offers protocol conversion between OSI and SNA. The combination of GTMOSI, OSNS, and OTSS is an OSI analog of CICS. IBM pronounced it Je t’aime OSI, although the words probably stuck in the corporate throat. Replaced by CSFI.
Guest: A second operating system that runs on the user’s primary operating system – e.g., VSE/ESA running as a guest under z/VM.
GUI: Graphical User Interface. Generic term for the WIMPS type interfaces used in OS/2, Windows, and the Macintosh. IBM has been involved to varying degrees in any number of GUIs – see AIXwindows, CUA1, Metaphor, Motif, NeXTStep, OpenLook, Presentation Manager, Windows, X-Terminal, X-Windows.
GUIDE: Guidance for Users of Integrated Data processing Equipment. For many years, an international user group for users of large IBM equipment. Main GUIDE interests were in applications and the commercial world. Depending on the area of the world, either stepped aside for SHARE or merged with SHARE. See also International User Group Council.
GUI Facility: A set of z/VM workstation agents, help files and modules available from the VM Download Library.