Browse Prior Art Database

Automatic Memory Validation for Subsetted Memory

IP.com Disclosure Number: IPCOM000108610D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Cox, DR: AUTHOR [+3]

Abstract

This article describes a method for providing memory validation of all subsetted memory that is owned by a process during termination. There is no way to verify that the subsetted memory in an OS/2* segment has not been corrupted.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Automatic Memory Validation for Subsetted Memory

       This article describes a method for providing memory
validation of all subsetted memory that is owned by a process during
termination.  There is no way to verify that the subsetted memory in
an OS/2* segment has not been corrupted.

      A process has access to memory at the segment level and can,
therefore, access all subsetted memory associated with a segment it
has access to.  OS/2 does not provide any protection of memory at the
subset level.  Memory subsets can be overwritten by any process with
access to the same segment.  There should be a way to validate that
all memory owned by a process has not been corrupted and to provide
notification when corruption is detected.

      In order to overcome this and other related memory problems in
our application systems, OfficeVision*/2 (OV/2) Office built a Memory
Management subsystem, providing a layer of independence between
applications programs and the OS/2 operating system.  This subsystem
is described in (1). Using this Memory Management subsystem as the
base, the subsystem was enhanced to provide memory prefix and suffix
information at the subset level.  This is described in (2). Each
subset of memory within this pool maintains both a prefix block and a
suffix block.  The prefix block contains a unique block identifier
and maintains the length of the subset and the inverted length of the
subset.

      Using this information, Memory Management can validate that
each subset of storage within a segment has not been corrupted by
ensuring that the prefix information is correct for each subset.  The
suffix block contains a unique block identifier and length.
Cross-checked with the prefix block, the Memory Management subsystem
can determine if the memory block has been corrupted.

      In order to facilitate automatic validation of all memory owned
by a proces...