上位內存塊
upper memory block
(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 {EMM}s can
provide UMB as well.
(1996-01-10)