cache line
a block of data associated with
a cache tag.
cache memory
See
cache
.
cache miss
a reference by the processor
to a memory location currently not housed in
the cache.
cache replacement
when a “cache miss”
occurs, the block containing the accessed lo-
cation must be loaded into the cache. If this
is full, an “old” block must be expelled from
the cache and replaced by the “new” block.
The “cache replacement algorithm” decides
which block should be replaced. An example
of this is the “Least Recently Used (LRU)”
algorithm, which replaces the block that has
gone the longest time without being refer-
enced.
cache synonym
See
cache aliasing
.
cache tag
a bit field associated with
each block in the cache. It is used to de-
termine where (and if) a referenced block re-
sides in the cache. The tags are typically
housed in a separate (and even faster) mem-
ory (the “tag directory”) which is searched
for in each memory reference. In this search,
the high order bits of the memory address
are associatively compared with the tags to
determine the block location. The number
of bits used in the tag depends on the cache
block “mapping function” used: “Direct-
mapped,” “Fully associative,” or the “Block-
set-associative” mapped cache.
CAD
See
computer-aided design
.
cage-rotor induction motor
an induction
motor whose rotor is occupied by copper or
aluminum bars, known as rotor bars, instead
of windings. Also commonly referred to as
a squirrel-cage induction motor.
calculating board
a single-phase scale
model of a power system that was used to
calculate power flows before the advent of
electronic computers.
calibration
the procedure of character-
izing the equipment in place for a particular
measurement set-up relative to some known
quantity, usually a calibration standard trace-
able to the National Institute for Standards
and Technology (NIST).
calibration kits
designed for use with
vector network analyzers. With these kits
you can make error-corrected measurements
of devices by measuring known devices
(standards) over the frequency range of in-
terest. Calibration standards include shorts,
open, sliding, and fixed loads.
calibration standards
a precision de-
vice used in the process of calibrating an EM
measurement system. It can be a standard
gain horn, an open, a short, a load, sphere,
etc., used to characterize an RCS, antenna,
or transmission line measurement system.
Most calibration standards are provided with
documentation that can be traced to a set of
standards at the NIST.
call instruction
(1) command within a
computer program that instructs the com-
puter to go to a subroutine.
(2) an instruction used to enter a subrou-
tine. When a call instruction executes, the
current program counter is saved on stack,
and the address of the subroutine (provided
by the call instruction) is used as the new pro-
gram counter.
calorimeter
a device used to determine
particle energies by measuring the ionization
of a particle shower in a heavy metal, usually
iron and lead.
CAM
acronym for content-addressable
memory or computer-aided manufacturing.
See
associative memory
,
computer-aided
manufacturing
.
c
2000 by CRC Press LLC