SEVENTH EDITION
`
`DICTIONARY
`ELECTRONICS
`
`RUDOLF F. GRAF
`
`L
`
`4
`
`Apple, Exhibit 1066, Page 1
`
`

`
`Newnes is an imprint of Butterworth-Heinemann.
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`Copyright © 1999 by Rudolf F. Graf
`
`A member of the Reed Elsevier Group.
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`Library of Congress Cataloging-in-Publication Data
`
`Graf, Rudolf F.
`Modern dictionary of electronics / Rudolf F. Graf. —7th ed.,
`revised and updated,
`p. (cid:9)
`cm.
`ISBN 0-7506-9866-7 (alk. paper)
`1. Electronics—Dictionaries. I. Title
`TK7804.G67 1999
`621.381'03—dc21 (cid:9)
`
`99-17889
`CIP
`
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`Apple, Exhibit 1066, Page 2
`
`

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`the ROM address lines are scanned. 9. A memory in
`which the contents are not intended to be altered during
`normal operation. The term read-only memory implies
`that the content is determined by its structure and is unal-
`terable (e.g., mask programmable ROM). Most ROMs are
`n x 8 (words x bits/word) to work with popular micro-
`processors. There are also special-purpose ROMs, such as
`character generators, with a 7-bit-wide output word and
`addressing structure to output one-hundred twenty-eight
`9 x 7 characters.
`readout — 1. The manner in which a computer dis-
`plays processed information—e.g., digital visual display,
`punched tape, automatic typewriter, etc. See also display.
`2. The information extracted from a memory device, such
`as a program store or call store. 3. The visual display of
`the output of a measuring instrument, or of a memory, or
`of a computer.
`readout device —In a computer, a device, con-
`sisting usually of physical equipment, that records the
`computer output either as a curve or as a set of printed
`numbers or letters.
`readout equipment — The electronic apparatus that
`provides indications and/or recordings of transducer out-
`put
`readout station — A recording or receiving radio
`station at which information is received as it is read out
`by the transmitter in a missile, probe, satellite, or other
`spacecraft. (The same station may serve also as a tracking
`station.)
`read pulse — 1. A pulse applied to one or more
`binary cells to determine whether a bit of information
`is stored there. 2. A pulse that causes information to be
`read out of a memory cell.
`readthrough — The continuous recovery in an audio
`channel of the target modulation, making possible rapid
`evaluation of the effectiveness of a jamming effort.
`read time —More commonly called access time.
`With respect to a memory, the interval between the time
`the read control and the address or location are present
`and the time the data output changes state.
`read/write check indicator— A device incorpo-
`rated in some computers to indicate, on interrogation,
`whether there was an error in reading or writing. The
`machine can be made to stop, attempt the operation again,
`or follow a special subroutine, depending on the result of
`the interrogation.
`read/write cycle —The sequence of operations
`required to read and write (restore) memory data.
`read/write cycle time—See cycle time.
`read/write head —1. The device that reads and
`writes information on tape, drum, or disk storage devices.
`2. The mechanism that writes data to or reads data from a
`magnetic recording medium. 3. An electromagnet capable
`of producing a switchable magnetic field to read and
`record bit streams.
`read/write memory — 1. A memory whose contents
`can be continuously changed quickly and easily during
`system operation. It differs from a read-only memory
`(ROM), whose contents are fixed and not subject to
`change, and a reprogrammable ROM, whose contents
`can be changed but only periodically. 2. A memory in
`which each cell may be selected by applying appropriate
`electrical input signals, and the stored data may be either
`(a) sensed at appropriate output terminals, or (b) changed
`in response to other similar electrical input signals.
`ready-to-receive signal —In a facsimile system,
`a signal returned to the transmitter to indicate that the
`receiver is ready to accept a transmission.
`real estate —Slang for the area on a printed circuit
`board or the surface of a wafer on which circuits can be
`built.
`
`readout — real-time spectrum analyzer
`
`real power— The component of apparent power that
`represents true work in an ac circuit. It is expressed in
`watts and is equal to the apparent power times the power
`factor.
`real time — 1. Having to do with the actual time
`during which physical events take place. 2. The perfor-
`mance of a computation during the actual time that the
`related physical process transpires in order that results
`of the computations are useful in guiding the physical
`process. 3. Refers to a type of operating system that sup-
`ports online equipment having critical time constraints.
`Events must be handled promptly (within set timing lim-
`its). Most process control and military command/control
`systems are real-time systems. 4. A computer process
`executed with sufficient speed so that the results of a
`process being monitored appear to be presented instan-
`taneously. The computer generally is able to present the
`results with sufficient speed to permit control changes to
`be made. See closed loop; open loop. 5. A computation
`or process by a computer using inputs derived from time-
`initiated events; the output resulting from the computation
`or processing can have an effect on and/or predict trends
`concerning those events. 6. Responding instantaneously,
`rather than delayed by transmission format. 7. The oper-
`ation of a program in the same time frame as a human
`being would.
`real-time clock — 1. A clock that indicates the
`passage of actual time, such as elapsed time in the flight
`of a missile, as opposed to some fictitious time established
`by a computer program. 2. A system clock that indicates
`actual elapsed time from some reference time (e.g., noon).
`3. A timing device used by a computer to derive elapsed
`time between events and to control processing of time-
`initiated event data. 4. A device that measures time at a
`rate consistent to the tasks being performed. Sometimes
`used for pacing the occurrence of events within a system.
`real-time data processing The processing of
`transactions as they occur, rather than hatching them.
`real-time executive-1. Supervisory software that
`allocates system resources among several tasks to allow
`them to perform necessary calculations in real time. The
`executive has responsibility for all priority scheduling,
`interrupt handling, timer service, physical control, inter-
`program communication, and queue maintenance required
`by real-time applications. 2. An operating system that
`runs the system in a real-time mode, typically required by
`online data communications or process-control systems.
`real-time input— Input information inserted into a
`system at the time it is generated by another system.
`real-time operating system — Operating system
`capable of real-time task management Includes event
`scheduling, interrupt management, and real-time event
`counters.
`real-time operation — 1. Operations performed on
`a computer in time with a physical process so that the
`answers obtained are useful in controlling that process.
`2. The use of a computer to control a process as it is
`actually occurring, necessitating, in general, relatively
`rapid operation on the part of the computer. 3. Data-
`processing technique in which information is utilized as
`events occur and the information is generated, as opposed
`to batch processing at a time unrelated to the time the
`information was generated.
`real-time output Output information removed
`from a system at the time it is needed by another system.
`real-time reaction — A computer function that
`immediately responds to, or causes, a physical application
`action.
`real-time spectrum analyzer — A device in which
`analysis of the spectrum of the incoming signal is
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`Apple, Exhibit 1066, Page 3