Browse Prior Art Database

Engineering Change Technique for Read Only Storage Program Store

IP.com Disclosure Number: IPCOM000084366D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Blevins, PR: AUTHOR

Abstract

The read-only storage (ROS) program store engineering change (EC) Technique implements an arbitrary program change (or EC) in a ROS program store. The technique uses an a priori established Pseudo-Essential Breakpoint Set of "hooks" to evoke a Breakpoint Monitor, which compares each "hooking" breakpoint to an Active Breakpoint Set. Whenever a match is found, then the code patch associated with the given active breakpoint is evoked. Both the Active Breakpoint Set and the associated code patches are contained in a programmable, pluggable memory.

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

Page 1 of 1

Engineering Change Technique for Read Only Storage Program Store

The read-only storage (ROS) program store engineering change (EC) Technique implements an arbitrary program change (or EC) in a ROS program store. The technique uses an a priori established Pseudo-Essential Breakpoint Set of "hooks" to evoke a Breakpoint Monitor, which compares each "hooking" breakpoint to an Active Breakpoint Set. Whenever a match is found, then the code patch associated with the given active breakpoint is evoked. Both the Active Breakpoint Set and the associated code patches are contained in a programmable, pluggable memory.

To insure that program execution can be intercepted before reaching an arbitrary instruction, means must be provided to identify at least a breakpoint for each series of sequentially executed, inline statements. A graph model of a program consists of modes (or instructions) of only 4 types, namely: SISO - Single Input Path with Single Output Path. MISO - Multiple Input Path with Single Output Path. SIMO - Single Input Path with Multiple Output Path. MIMO - Multiple Input Path with Multiple Output Path.

With respect to combinations or graphs of these mode types, program execution can always be intercepted before reaching an arbitrary mode if breakpoints are introduced at all MISO and MIMO type modes plus all modes corresponding to execution initiation points due to deadstart, interrupts and out- of-line execution transitions. The collection of all such modes defines the Essential Breakp...