By IBM

Reprint Courtesy of International Business Machines Corporation, © International Business Machines Corporation

This is the standard IBM SDK/DDK Glossary that is used by multiple documents including the Virtual Device Driver Reference for OS/2, MMPM/2 Device Driver Reference, Display Device Driver Reference for OS/2, Virtual Device Driver Reference for OS/2, Printer Device Driver Reference for OS/2, Storage Device Driver Reference, GRADD Reference Glossary, Input Output Device Driver Reference and others.

Glossary

This glossary contains terms and definitions that are, for the most part, used for OS/2 products. This is not a complete dictionary of computer terms.

Introduction

This glossary defines many of the terms used in this book. It includes terms and definitions from the IBM Dictionary of Computing, as well as terms specific to the Presentation Manager, but it is not a complete glossary for OS/2.

Other primary sources for these definitions are:

The American National Standard Dictionary for Information Systems, ANSI X3 .172-1990, copyrighted 1990 by the American National Standards Institute, 11 West 42nd Street, New York, New York 10036. These definitions are identified by the symbol (A) after the definition.
The Information Technology Vocabulary, developed by Subcommittee 1, Joint Technical Committee 1, of the International Organization for Standardization and the International Electrotechnical Commission (ISO/IEC JTC1/SC1). Definitions of published parts of this vocabulary are identified by the symbol (I) after the definition; definitions taken from draft international standards, committee drafts, and working papers being developed by ISO/IEC JTC1/SC1 are identified by the symbol (T) after the definition, indicating that final agreement has not yet been reached among the participating National Bodies of SC1.

Glossary

A

B

C

D

E

F

G

H

handle - (1) An identifier that represents an object, such as a device or a window, to the Presentation Interface. (2) In the Advanced DOS and OS/2 operating systems, a binary value created by the system that identifies a drive, directory, and file so that the file can be found and opened.

handshaking - A method by which two pieces of hardware, such as a personal computer and a plotter, can communicate. Depending upon the devices communicating, handshaking occurs either as a hardware function or through software, such as a device driver.

hard error - An error condition on a network that requires that the network be reconfigured or that the source of the error be removed before the network can resume reliable operation.

hardware palette - The array of RGBs that the physical device is displaying .

heap - An area of free storage available for dynamic allocation by an application. Its size varies depending on the storage requirements of the application.

hex - See hexadecimal

hexadecimal - Pertaining to a system of numbers to the base 16; hexadecimal digits range from 0 through 9 and A through F, where A represents 10 and F represents 15.

hook - A point in a system-defined function where an application can supply additional code that the system processes as though it were part of the function.

hook chain - A sequence of hook procedures that are "chained" together so that each event is passed in turn to each procedure in the chain.

I

J

journal

K

L

M

N

P

physical address - A 32-bit byte address giving the actual address in physical storage for a data item.

physical device driver (PDD) - A system interface that handles hardware interrupts and supports a set of input and output functions.

pipe - See named pipe, unnamed pipe.

picture element (pel, pixel) - (1) In computer graphics, the smallest element of a display surface that can be independently assigned color and intensity. (T) . (2) The area of the finest detail that can be reproduced effectively on the recording medium. (3) An element of a raster pattern about which a toned area on a photoconductor can appear.

PIO - Programmed I/O.

pixel - Picture element.

polyfillet - A curve based on a sequence of lines. The curve is tangential to the end points of the first and last lines, and tangential also to the midpoints of all other lines.

polyline - In computer graphics, a sequence of adjoining lines.

pop - To remove an item from the top of a pushdown list. Contrast with push .

prefetch - To locate and load a quantity of data in anticipation of a request.

presence-check function - A Ring 3 (non-privileged) .EXE program that determines whether a given hardware interface is present on a workstation.

PRESENCECHECK - A keyword, interpreted by the DDINSTAL utility, to determine whether to process the device driver profile file, based on the return code from PRESENCECHECK.

printer driver - A file that describes the physical characteristics of a printer, plotter, or other peripheral device, and is used to convert graphics and text into device-specific data at the time of printing or plotting.

Print Manager - In the Presentation Manager, the part of the spooler that manages the spooling process. It also allows the user to view print queues and to manipulate print jobs.

privilege level - A method of protection that allows only certain program instructions to be used by certain programs.

program group - Several programs that can be acted upon as a single entity.

protect mode - A method of program operation that limits or prevents access to certain instructions or areas of storage. Contrast with real mode.

push - To add an item to the top of a pushdown list. Contrast with pop.