or by any means without the written permission of the publisher.
`
`Library of Congress Cataloging-in-Publication Data
`Microsoft Computer Dictionary. -- 4th ed.
`p. cm.
`
`Previous eds. published under title: Microsoft Press computer
`dictionary
`ISBN 0-7356-0615-3
`
`2. Microcomputers Dictionaries.
`1. Computers Dictionaries.
`I. Microsoft Press computer dictionary.
`QA76.l5.M538
`1999
`
`004'.O3--dc21
`
`-
`
`99-20168
`CIP
`
`Printed and bound in the United States of America.
`
`3456789 MLML 43210
`
`Distributed in Canada by Penguin Books Canada Limited.
`
`A CIP catalogue record for this book is available from the British Library.
`
`Microsoft Press books are available through booksellers and distributors worldwide. For further information
`about international editions, contact your local Microsoft Corporation office or contact Microsoft Press
`International directly at fax (425) 936-7329. Visit our Web site at mspress.microsoft.com.
`
`Macintosh, Power Macintosh, QuickTime, and TrueType fonts are registered trademarks of Apple Computer,
`Inc. Kodak is a registered trademark of the Eastman Kodak Company. Intel is a registered trademark and Indeo
`is a trademark of Intel Corporation. Active Desktop, Active Directory, ActiveMovie, Active Platform, ActiveX,
`Authenticode, BackOffice, Directlnput, DirectX, Microsoft, Microsoft Press, MS-DOS, MSN, NetMeeting,
`NetSh0w, Visual Basic, Visual C++, Visual J++, WebTV, WebTV Network, Win32, Win32s, Windows,
`Windows NT, and XENIX are either registered trademarks or trademarks of Microsoft Corporation in the
`United States and/or other countries. PANTONE is a registered trademark of Pantone, Inc. Other product and
`company names mentioned herein may be the trademarks of their respective owners.
`
`The example companies, organizations, products, people, and events depicted herein are fictitious. No associa-
`tion with any real company, organization, product, person, or event is intended or should be inferred.
`
`Acquisitions Editor: Christey Bahn
`Project Editor: Kim Fryer
`
`

`
`ware system. A hardware monitor can detect the
`cause of a fatal error such as a system crash, whereas
`a software monitor or debugger cannot. Compare
`debugger.
`
`hardware profile n. A set of data that describes the
`configuration and characteristics of a given piece of
`computer equipment. Such data is typically used to
`configure computers for use with peripheral devices.
`hardware tree n. In Windows 9x, a data structure
`containing information about the configuration and
`requirements of a system’s hardware devices. Con-
`sisting of nodes that point to active devices, the hard-
`ware tree is dynamic and is reconstructed every time
`the operating system is started or refreshed. The
`hardware tree facilitates the Plug and Play capability
`of Windows 9x.
`
`hardwired adj. 1. Built into a system using hardware
`such as logic circuits, rather than accomplished
`through programming. 2. Physically connected to a
`system or a network, as by means of a network con-
`nector board and cable.
`
`Harvard architecture 11. A processor architecture that
`uses separate address buses for code and for data.
`This increases throughput by allowing the system to
`fetch instructions at the same time that it reads and
`writes data. This architecture also allows optimiza-
`tion of memory system design because instructions
`tend to be fetched sequentially, whereas data reads
`and writes are more random.
`
`Harvard Mark I n. See Mark I.
`
`hash‘ n. In many FTP client programs, a command
`that instructs the FTP client to display a pound sign
`(#) each time it sends or receives a block of data. See
`also FTP client.
`
`search, hashz, linear search, search algorithm.
`
`hash total 11. An error-checking value derived from
`the addition of a set of numbers taken from data (not
`necessarily numeric data) that is to be processed or
`manipulated in some way. After processing, the hash
`total is recalculated and compared with the original
`total. If the two do not match, the original data has
`been changed in some way.
`
`Hayes-compatible adj. Responding to the same set
`of commands as the modems manufactured by
`
`Hayes Microcomputer Products. This command set
`has become the de facto standard for microcom-
`puter modems.
`HDBMS n. See hierarchical database management
`system.
`HDF n. See Hierarchical Data Format.
`
`HDLC n. Acronym for High—level Data Link Control.
`A protocol for information transfer adopted by the
`ISO. HDLC is a bit-oriented, synchronous protocol
`that applies to the data-link (message-packaging)
`layer (layer 2 of the ISO/OSI reference model) for
`computer-microcomputer communications. Messages
`are transmitted in units called frames, which can con-
`tain differing amounts of data but which must be or-
`ganized in a particular way. See also frame
`(definition 1), ISO/OSI reference model.
`
`HDSL n. Acronym for High-bit-rate Digital Sub-
`scriber Line. A form of DSL, HDSL is a protocol for
`
`digital transmission of data over standard copper
`telecommunications lines (as opposed to fiber-optic
`lines) at rates of 1.544 Mbps in both directions. Also
`called High-data-rate Digital Subscriber Line. See
`also DSL.
`
`hash‘ vb. To be mapped to a numerical value by a
`transformation known as a hashing function. Hashing
`is used to convert an identifier or key, meaningful to a
`user, into a value for the location of the corresponding
`data in a structure, such as a table. For example, given
`
`HDTV 11. Acronym for high-definition television. A
`method of transmitting and receiving television sig-
`nals that produces a picture with much greater reso-
`lution and clarity than does standard television
`technology.
`
`
`
`

`
`body of the program. See also procedure.
`
`processl n. A program or part of a program; a coher-
`ent sequence of steps undertaken by a program.
`
`process‘ vb. To manipulate data with a program.
`
`process-bound adj. Limited in performance by pro-
`cessing requirements. See also computation-bound.
`
`process color n. A method of handling color in a
`document in which each block of color is separated
`into its subtractive primary color components for
`printing: cyan, magenta, and yellow (as well as
`black). All other colors are created by blending lay-
`ers of various sizes of halftone spots printed in cyan,
`magenta, and yellow to create the image. See also
`color model, color separation (definition 1). Compare
`spot color.
`
`processing n. The manipulation of data within a com-
`puter system. Processing is the vital step between
`receiving data (input) and producing results (out-
`put)—the task for which computers are designed.
`
`processor 11. See central processing unit, micropro-
`cessor.
`
`Processor Direct Slot n. See PDS (definition 1).
`
`Processor Input/Output n. See PIO.
`
`Prodigy Information Service 11. An online inforrna—
`tion service founded by IBM and Sears. Like its
`competitors America Online and CompuServe,
`Prodigy offers access to databases and file libraries,
`online chat, special interest groups, e-mail, and
`Internet connectivity. Also called Prodigy.
`
`product n. 1. An operator in the relational algebra
`used in database management that, when applied to
`two existing relations (tables), results in the creation
`of a new table containing all possible ordered concat-
`enations (combinations) of tuples (rows) from the
`first relation with tuples from the second. The num-
`ber of rows in the resulting relation is the product of
`the number of rows in the two source relations. Also
`
`approach that uses a set of rules, a database of infor-
`mation, and a “rule interpreter” to match premises
`with facts and form a conclusion. Production systems
`are also known as rule—based systems or inference
`systems. See also expert system.
`
`Professional Graphics Adapter n. A video adapter
`introduced by IBM, primarily for CAD applications.
`The Professional Graphics Adapter is capable of dis-
`playing 256 colors, with a horizontal resolution of
`640 pixels and a vertical resolution of 480 pixels.
`Acronym: PGA.
`
`Professional Graphics Display 71. An analog display
`introduced by IBM, intended for use with their Pro-
`fessional Graphics Adapter. See also Professional
`Graphics Adapter.
`
`profile‘ n. See user profile.
`
`profile’ vb. To analyze a program to determine how
`much time is spent in different parts of the program
`during execution.
`
`Profiles for Open Systems Internetworking
`Technology 11. See POSIT.
`
`program‘ 11. A sequence of instructions that can be
`executed by a computer. The term can refer to the
`original source code or to the executable (machine
`language) version. Also called software. See also
`program creation, routine, statement.
`program‘ vb. To create a computer program, a set of
`instructions that a computer or other device executes
`to perform a series of actions or a particular type of
`work.
`
`program card n. See PC Card, ROM card.
`
`program cartridge n. See ROM cartridge.
`
`program counter n. A register (small, high-speed
`memory circuit within a microprocessor) that con-
`tains the address (location) of the instruction to be
`executed next in the program sequence.