Browse Prior Art Database

Using Split Memory to Back-Up System Memory

IP.com Disclosure Number: IPCOM000113217D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Schmitt, EJ: AUTHOR [+2]

Abstract

Disclosed is a feature for using split memory, from 640K to 1M, to back-up system memory in case of system memory failure. Without this feature, most of the split memory has generally been remapped to locations above the last valid location of system memory. However, as ROM is mapped to RAM, and as advanced power management functions take up most of the split memory, the last 128K of split memory is not remapped. With this feature, this portion of memory, which otherwise remains unused, can be used as a replacement for any failed system memory in a back-up process not requiring user intervention. This feature extends memory field life and overall system availability.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 82% of the total text.

Using Split Memory to Back-Up System Memory

      Disclosed is a feature for using split memory, from 640K to 1M,
to back-up system memory in case of system memory failure.  Without
this feature, most of the split memory has generally been remapped to
locations above the last valid location of system memory.  However,
as ROM is mapped to RAM, and as advanced power management functions
take up most of the split memory, the last 128K of split memory is
not remapped.  With this feature, this portion of memory, which
otherwise remains unused, can be used as a replacement for any failed
system memory in a back-up process not requiring user intervention.
This feature extends memory field life and overall system
availability.

      IBM PS/2* Systems record any failure in memory by logging the
address of failing memory to Non-Volatile Random-Access Memory
(NVRAM).  With this feature, the system then replaces this failed
memory with split memory that has not been remapped.  The process,
which includes alerting the system management handler of the
operating system and activating the split memory to replace the
failed memory, is accomplished in a manner which is transparent to
the user and to the application program.  When this process is
completed, system operation is resumed, so that minimal performance
degradation is achieved.

      This feature may be used during system operation, or at
power-on time under the control of POST (Power-On Self Test)
routines.  Th...