primary cache

from The Free On-line Dictionary of Computing (8 July 2008)

primary cache
L1 cache
level 1 cache
level one cache

   <hardware, architecture> (L1 cache, level one cache) A small,
   fast {cache} memory inside or close to the {CPU} chip.

   For example, an {Intel 80486} has an eight-{kilobyte} on-chip
   cache, and most {Pentiums} have a 16-KB on-chip level one
   cache that consists of an 8-KB {instruction cache} and an 8-KB
   {data cache}.

   The larger, slower {secondary cache} is normally connected to
   the CPU via its external {bus}.

   (1997-06-25)