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Permanent Alteration of Control Programs Loaded from Read/Write Disk Stores into Volatile Control Stores

IP.com Disclosure Number: IPCOM000079008D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Kraft, KL: AUTHOR [+4]

Abstract

Permanent changes (e.g., line mode setting for Integrated Communication Adaptors ICA) and corrections of control programs loaded from disk stores into volatile-control stores, call for appropriate modification of the disk file. However, due to formatting problems and speed and space variations, an update-in-place procedure for disk records has proved to be unfeasible; instead, the whole disk (or diskette) had to be rewritten or replaced.

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Permanent Alteration of Control Programs Loaded from Read/Write Disk Stores into Volatile Control Stores

Permanent changes (e.g., line mode setting for Integrated Communication Adaptors ICA) and corrections of control programs loaded from disk stores into volatile-control stores, call for appropriate modification of the disk file. However, due to formatting problems and speed and space variations, an update-in-place procedure for disk records has proved to be unfeasible; instead, the whole disk (or diskette) had to be rewritten or replaced.

The present arrangement provides the facility of recording (once or repeatedly) change information for the control program in a "patch" area of the disk store, with smaller block sizes and greater interrecord gaps than those used for control code records, and of updating the control code automatically after it has been loaded into the control store by a special patch loader. The control code changes, which are transferred to and linked with the disk patch area by special programs, can be entered into the system via keyboard or by data transmission.

The disk patch area is illustrated in the drawing. It comprises an identifier table ID, indicating to the patch loader the presence of alterations, and each entry of which contains the program identifier as well as the start and end addresses for the corresponding alteration data blocks. In addition, it includes alteration data blocks proper, consisting of the code to be replaced, p...