random access -- Definition

In the  context of computing, random  access means that an  entity, such as
memory, can  be accessed  at any  point, not just  at the  beginning.  This
means that all points within  memory can be accessed equally quickly.  This
contrasts with  sequential access, in which entities must  be accessed in a
particular  order, so  that some  entities  take longer  to access  than do
others.

A tape drive  is an example of a sequential  access device, i.e., the order
in which data  are read is dictated by the  order in which they stream past
the tape head.  Random-access memory  (RAM) is an example of random access.
Hard  disks  and  floppy  disks  combine  elements  of  random  access  and
sequential access.

RAM, which  usually consists of semiconductor  integrated circuits, is also
strictly  random access.   In  this regard,  the term  ``RAM'' is  slightly
misleading;  a  more  accurate  name  would  be ``read/write  memory'',  to
contrast  RAM with  read-only  memory (ROM),  which is  also random  access
memory.

See Also

read-only memory,
Programming COHERENT

© 2012 by Stephen A. Ness