Browse Prior Art Database

Algorithm for Enhanced Virtual Memory

IP.com Disclosure Number: IPCOM000116900D
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Celi Jr, J: AUTHOR [+3]

Abstract

Disclosed is the modification of a Virtual Memory Subsystem, so that spare video memory is used to store memory pages, which are therefore not swapped to disk memory. In a preferred implementation, a memory management section is added to the video driver, with this subsection acting as a memory server to the virtual memory subsystem of the system.

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Algorithm for Enhanced Virtual Memory

      Disclosed is the modification of a Virtual Memory Subsystem, so
that spare video memory is used to store memory pages, which are
therefore not swapped to disk memory.  In a preferred implementation,
a memory management section is added to the video driver, with this
subsection acting as a memory server to the virtual memory subsystem
of the system.

      Conventional Super Video Graphics Adapter (VGA) video adapters
often have 2 to 4 Megabytes (Mb) of video memory, which is only used
for video data, such as the actual screen image, icons, and video
fonts.  Since higher resolution video modes require more system
resources other than video memory, systems having limited memory are
generally run at relatively low video resolution modes, leaving
considerable portions of video memory unused.  For example, a
640x480x16 video mode requires 154K of video memory, and a
640x480x256 video mode requires 308K of video memory.  Thus, 1Mb to

3Mb of video memory can be freed for other users.  In a system having
4Mb of system Random Access Memory (RAM), an increase in system
memory
of even only 512K produces a noticeable improvement in performance.