Online Computer Terms Dictionary - C

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)

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).

	ints = from 1  where  from n = n : from (n+1)

[The Implementation of Functional Programming Languages, Simon Peyton Jones].

(2006-10-12)

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)

Constantine/Yourdon

Yourdon/Constantine

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)

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.