Browse Prior Art Database

Software Storage Protect

IP.com Disclosure Number: IPCOM000052800D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Solly, DC: AUTHOR [+3]

Abstract

This article describes a technique for detecting errors in storage addressing in a multi-tasking environment.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 69% of the total text.

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Software Storage Protect

This article describes a technique for detecting errors in storage addressing in a multi-tasking environment.

When a task, running in a microprocessor with multiple priority interrupt levels, but without hardware protection to main storage, includes an addressing error, the error will corrupt storage allocated to other tasks. The consequence is the random failure of other tasks and the random corruption of data stored on any non-volatile storage. In a system with complex control programs and multiple application tasks it becomes impossible to interpret errors or reproduce them even under the most carefully controlled conditions.

The technique described below is to produce multiple tasking application programs with object code in which STORE instructions have been converted to unique invalid operations. This can be done using any of the following techniques:

- Compiler or assembler options to produce modified object code.

- Special macros to produce modified object code.

- Special object code processing programs to modify previously produced object code.

The control program is modified, if it has task roll in/roll out facilities, to force tasks to roll out whenever eligible, and not only when storage utilization levels require it.

The control program is also modified to release storage to the opposite end of the free storage chain to that from which it is allocated, and to destroy data in released areas.

Function is added to the control pr...