US 4,189,773 AGranted

On-line memory space allocation

AssigneeGeneral Electric Company

InventorMichael F. O'Meara

Life of this patent

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Abstract

A programmable data processor or controller serving as the main control in a control system contains an executive program for controlling the transfer of information between the processor and system equipment, updating that information during on-line control of the equipment and modifying the executive program to change operating parameters of the system while the data processor is controlling the system equipment. Modification of the executive program and displaying of system parameters relative to the executive program and the system equipment is accomplished through the use of an operator's console which communicates with the data processor and system equipment as a result of operator intervention.

Claims11

Dependent claims

In an on-line data processing system for controlling equipment, a method, by means of an improved executive program, of changing at least a segment of an on-line application program and of optimizing memory space utilization by assuring contiguous positions of identifiable program segments comprised of instructions located in the memory after modification of a segment size while without interruption continuing the control of the equipment in accordance with the instructions in the modified segment comprising the steps:

(A) providing in the memory at least first, second and third portions,
(1) said first portion retaining said improved executive program governing the operation of the data processing system,
(2) said second portion having located therein a repetitively executable application program comprised of a plurality of individually identifiable segments disposed contiguously to one another, the instructions thereof being representative of logical states for controlling the equipment, and
(3) said third portion serving as a temporary store for a desired replacement segment which is to replace a segment in said second portion;
(B) inserting, under control of the executive program, a first branch instruction in the first memory instruction location of the segment to be replaced and a second branch instruction after the last instruction location of the replacement segment so that the application program is still repetitively executable by using the replacement segment while that segment is still in the third portion;
(C) determining, under control of the executive program, the amount of memory space that the replacement segment will occupy in the second portion;
(D) moving, under control of the executive program, all the application program segments in the memory following the segment to be replaced in said second portion in dependence upon the space requirements determined for said replacement segment;
and
(E) writing, under control of the executive program, said replacement segment into the second portion of the memory in the space created by the moving of all the segments.

6 more elements

(A) providing in the memory at least first, second and third portions,
(1) said first portion retaining said improved executive program governing the operation of the data processing system,
(2) said second portion having located therein a repetitively executable application program comprised of a plurality of individually identifiable segments disposed contiguously to one another, the instructions thereof being representative of logical states for controlling the equipment, and
(3) said third portion serving as a temporary store for a desired replacement segment which is to replace a segment in said second portion;
(B) writing, under control of the executive program, a segment to be modified from said second memory portion to said third memory portion;
(C) inserting, under control of the executive program, a first branch instruction in the first memory location of the segment to be replaced and a second branch instruction after the last word of the replacement segment so that the application program may still be run using the replacement segment while that segment is in the third portion;
(D) modifying, under control of the executive program, the copied segment located in said third memory portion;
(E) determining, under control of the executive program, the amount of space that the replacement segment will occupy in the second portion;
(F) adjusting, under control of the executive program, the application program segments in the memory immediately adjacent the segment to be replaced to provide adequate space in said second portion required by said replacement segment;
and
(G) writing, under control of the executive program, said replacement segment into the provided space while removing the branch instruction from the first memory location of the segment to be replaced.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/485,572Filed 3 Jul 1974
Granted: 19 Feb 1980
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G05B 19/056
Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts: programming the PLC
G05B 2219/13153
Plc programming: modification, change of program in real time
G05B 2219/15065
Plc structure of the system: optimize program memory space
G05B 2219/36078
Nc in input of data, input key till input tape: insert, read in new command instruction to modify fixed program

Family

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