Upper Memory Block

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

upper memory block

   <storage> (UMB) Up to 64 {kilobytes} of the {expanded memory
   page frame} above the first 64 kilobytes.  The UMB can be used
   to store {TSR} programs or {device drivers} thereby freeing
   parts of the precious {conventional memory}.  The UMB is
   provided by special memory manager programs; many {EMMs} can
   provide UMB as well.

   (1996-01-10)