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`IEEE 100
`The Authoritative Dictionary of
`IEEE Standards Terms
`
`Seventh Edition
`
`Published by
`Standards Information Network
`IEEE Press
`
`

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`read-around ratio
`
`931
`
`read-only file system
`
`adjacent to any given storage element without more than a
`specified loss of information from that element. Note: The
`sequence of operations (including priming, writing, or eras-
`ing), and the storage elements on which the operations are
`performed, should be specified. See also: storage tube.
`(ED) 158-1962w,161-1971w
`read-around ratio* (1) (FASTBUS acquisition and control)
`A cycle in which the direction of data flow is from slave(s)
`toward a master. Synonym: read.
`(NID) 960-1986s
`(2) (VMEbus) A data transfer bus (DTB) cycle that is used
`to transfer 1, 2, 3, or 4 bytes from a slave to a master. The
`cycle begins when the master broadcasts an address and an
`address modifier. Each slave captures the address and the ad-
`dress modifier, and verifies if it will respond to the cycle. If
`it is intended to respond, it retrieves the data from its internal
`storage, places it on the data bus and acknowledges the transfer.
`The master then terminates the cycle.
`(BA/C) 1014-1987
`(3) See also: read-around number.
`* Deprecated.
`read-back check See: echo check.
`
`read circuitry That part of the memory that is used in trans-
`ferring the stored data from the memory section to external
`circuitry.
`(ED) 1005-1998
`read cycle (1) A data transfer bus (DTB) cycle that is used to
`transfer 1, 2, 3, or 4 bytes from a slave to a master. The cycle
`begins when the master broadcasts an address and an address
`modifier. Each slave captures the address and the address
`modifier, and verifies if it will respond to the cycle. If it is
`intended to respond, it retrieves the data from its internal stor-
`age, places it on the data bus, and acknowledges the transfer.
`The master then terminates the cycle.
`(C/BA) 1014-1987
`(2) (read) A cycle in which the direction of data flow is from
`slave(s) toward a master.
`(NID) 960-1993
`(3) A cycle in which data are transferred from some storage
`location to the device that requested the read. Contrast: write
`cycle.
`(C) 610.10-1994w
`read cycle time The minimum time interval between the starts
`of successive read cycles in a storage device that has separate
`read and write cycles. Contrast: write cycle time.
`(C) 610.10-1994w
`read data transfer One or more data transfers from a replying
`agent to a bus owner, with uninterrupted bus ownership.
`(C/MM) 1296-1987s
`read delay trd (metal-nitride-oxide field-effect transistor)
`Time period between the end of the writing pulse and the start
`of the read condition.
`(ED) 581-1978w
`read disturb (1) (metal-nitride-oxide field-effect transistor)
`A change in the instantaneous threshold voltage of a metal-
`nitride-oxide-semiconductor (MNOS) transistor due to the
`very act of measuring it.
`(ED) 581-1978w
`(2) The corruption of data that
`is caused by reading the
`memory.
`(ED) 1005-1998
`read disturb cycles The number of consecutive read cycles that
`occur before a memory state becomes indistinguishable, due
`solely to reading.
`(ED) 641-1987w
`reader (1) (A) An input device that is capable of sensing stored
`information, and of conveying that information into on-line
`storage. (B) Any device which can sense, detect, or convert
`data from one medium to another. See also: character reader;
`paper tape reader; optical mark reader; badge reader; card
`reader.
`(C) 610.10-1994
`(2) A component of a roadside beacon that provides the ca-
`pabilities for radio wave communications with a transponder.
`(SCC32) 1455-1999
`reader note A comment made by a reader about an diagram
`and placed on the diagram page. A reader note is not part of
`the diagram itself, but rather is used for communication about
`a diagram during model development.
`
`(C/SE) 1320.1-1998
`read frame The transfer of data from a Smart Transducer In-
`terface Module to a Network Capable Application Processor.
`(IM/ST) 1451.2-1997
`
`read head (1) (test, measurement, and diagnostic equipment)
`A sensor that converts information stored on punched tape,
`magnetic tape, magnetic drum, and so forth into electrical
`signals.
`(MIL) [2]
`(2) A head capable only of reading information from the stor-
`age medium. Synonym: playback head. Contrast: write head;
`read/write head. See also: pre-read head.
`
`(C) 610.10-1994w
`readily accessible (packaging machinery) (power and distri-
`bution transformers) Capable of being reached quickly for
`operation, renewal, or inspections, without requiring those to
`whom ready access is requisite to climb over or remove ob-
`stacles or to resort to portable ladders, chairs, etc.
`(NEC/NESC/IA/PE/PKG/1"R) 333-1980w,
`C57.12.80-1978r, [86]
`readily climbable Having sufficient handholds and footholds to
`permit an average person to climb easily without using a lad-
`der or other special equipment.
`(NESC) C2-1997
`readiness test (test, measurement, and diagnostic equip-
`ment) A test specifically designed to detennine whether an
`equipment or system is operationally suitable for a mission.
`(MIL) [2]
`reading (1) (recording instrument) The value indicated by the
`position of the index that moves over the indicating scale. See
`also: accuracy rating.
`(EEC/PE) [119]
`(2) (radiation instrumentation) The indicated value of the
`readout.
`(N1) N42.17B-1989r
`reading rate (storage tubes) The rate of reading successive
`storage elements. See also: storage tube.
`(ED) 158-1962w
`reading speed (storage tubes) See also: storage tube; data
`processing.
`(ED) 158-1962w, 161-1971w
`reading speed, minimum usable See: minimum usable reading
`speed.
`reading time (storage tubes) The time during which stored
`information is being read. See also: storage tube.
`(ED) 158-1962w
`reading time, maximum usable See: maximum usable reading
`time.
`
`read-in lag (diode-type camera tube) The fraction of the
`steady-state ON signal that is read out in any field after ini-
`tiation of irradiance.
`(ED) 503-1978w
`read-modify-write cycle A data transfer bus (DTB) cycle that
`is used to both read from, and write to, a slave location with-
`out pennitting any other master to access that location. This
`cycle is most useful in multiprocessing systems where certain
`memory locations are used to provide semaphore functions.
`(C/BA) 1014-1987
`read-modify-write (RMW) cycle A cycle in which an item is
`read, its contents are modified, and then is written back to
`storage in a single operation. See also: write cycle; read cycle.
`(C) 610.10-1994w
`read-mostly devices (metal-nitride-oxide field-effect transis-
`tor) Metal-nitride-oxide semiconductor (MNOS) memory
`transistors whose retention under constant read condition is
`
`in excess of one year. This makes these devices applicable in
`electrically-alterable read-only memories (EAROMS). A typ-
`ical writing pulse width is one ms.
`(ED) 581-1978w
`read number, maximum usable See: maximum usable read
`number.
`
`read-only (1) Pertaining to a storage medium which can only
`be read from. Contrast: write-once/read-many; read/write.
`(C) 610.10-1994w
`(2) A property that causes no state changes, i.e., it does no
`updates.
`(C/SE) 1320.2-1998
`read-only access A type of access to data in which the data may
`be read but not changed or deleted. Synonym: fixed. Contrast:
`read/write access. See also: update access; delete access;
`write access.
`(C) 610.5-1990w
`read-only file system A file system that has implementation-
`defined characteristics restricting modifications.
`(C/PA) 9945-1-1996, 9945-2-1993, 1003.5-1999