constant angular velocity
<storage> (CAV) A disk driving scheme in which the angular velocity of
the disk is kept constant. This means that the linear velocity of the disk be
larger when the reading or writing the outer tracks. The disadvantage of this
technique is that the read/write speed varies from track to track. However, as
mechanical stability puts an upper limit on the angular velocity (and not the
linear velocity) this allows the full potential of the drive is used.
(1998-03-27)
Nearby terms:
console « console jockey « Consortium for Lexical
Research «
constant angular velocity » constant applicative
form » constant folding » Constantine/Yourdon
constant applicative form
<functional programming> (CAF) A supercombinator which is not a lambda
abstraction. This includes truly constant expressions such as 12, (+ 1 2), [1,
2, 3] as well as partially applied functions such as (+ 4). Note that this last
example is equivalent under eta abstraction to \ x . + 4 x which is not a CAF.
Since a CAF is a supercombinator, it contains no free variables. Moreover, since
it is not a lambda abstraction it contains no variables at all. It may however
contain identifiers which refer to other CAFs, e.g.
c 3 where c = (* 2).
A CAF can always be lifted to the top level of the program. It can either
be compiled to a piece of graph which will be shared
by all uses or to some shared code which will
overwrite itself with some graph the first time it
is evaluated. A CAF such as
ints = from 1 where from n = n : from (n+1)
can grow without bound but may only be accessible from within the code of
one or more functions. In order for the garbage
collector to be able to reclaim such structures, we
associate with each function a list of the CAFs to
which it refers. When garbage collecting a reference
to the function we collect the CAFs on its list.
[The Implementation of Functional Programming Languages, Simon Peyton Jones].
(2006-10-12)
Nearby terms:
console jockey « Consortium for Lexical Research «
constant angular velocity « constant applicative
form » constant folding » Constantine/Yourdon »
constant linear velocity
constant folding
<compiler> A compiler optimisation technique where constant
subexpressions are evaluated at compile time. This is usually only applied to
built-in numerical and boolean operators whereas partial evaluation is more
general in that expressions involving user-defined functions may also be
evaluated at compile time.
(1997-02-20)
Nearby terms:
Consortium for Lexical Research « constant angular
velocity « constant applicative form « constant
folding » Constantine/Yourdon » constant linear
velocity » constant mapping
Constantine/Yourdon
Yourdon/Constantine
Nearby terms:
constant angular velocity « constant applicative
form « constant folding « Constantine/Yourdon
» constant linear velocity » constant mapping »
constraint
constant linear velocity
<storage> (CLV) A disk driving scheme in which the linear velocity of the
disk is kept constant. This requires that the angular velocity of the disk be
larger when the reading or writing tracks closer to the axis. The advantage of
this technique is that the read/write speed is constant. However, as mechanical
stability puts an upper limit on the angular velocity (and not the linear
velocity) using the same linear velocity throughout, i.e., using less then the
maximal angular velocity at outer tracks means that the full potential of the
drive is not used.
(1998-03-27)
Nearby terms:
constant applicative form « constant folding «
Constantine/Yourdon « constant linear velocity
» constant mapping » constraint » constraint
functional programming
constant mapping
Some TCP software constructs the destination Ethernet address from the top 24
bits of the Ethernet address followed by the low 24 bits of the (class A)
destination Internet address. For this scheme the top 24 bits of the Ethernet
address must be the same on all hosts on the net. Contrast ARP.
Nearby terms:
constant folding « Constantine/Yourdon « constant
linear velocity « constant mapping »
constraint » constraint functional programming »
Constraint Handling In Prolog
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