Browse Prior Art Database

IPL Record Extension for Alternate Boot Programs

IP.com Disclosure Number: IPCOM000038115D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Birgen, GC: AUTHOR [+2]

Abstract

Disclosed is a method of extending an IPL (Initial Program Load) record to permit multiple boot programs to be loaded from the same device.

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IPL Record Extension for Alternate Boot Programs

Disclosed is a method of extending an IPL (Initial Program Load) record to permit multiple boot programs to be loaded from the same device.

The information in an IPL record is used by the IPL ROM code to load a software program, herein called a boot program, from the IPL device into memory. An IPL record normally consists of a media description and a boot program description. The media description describes physical characteristics of the IPL device, for example number of tracks and number of sectors per track. The boot record description describes characteristics of a boot program located on the IPL device, for example, boot program location and length.

By replicating the boot program description, multiple boot programs and therefore multiple operating environments can reside on a single IPL device and IPL ROM can be coded to load any of the boot programs described in the boot record. For example, in a system with a single disk device, both the operating system and the diagnostics operating environment can reside on the same device and IPL ROM can be coded to sense a system condition, such as keyswitch position and load the operating system's boot program if the keyswitch is in the 'normal' position or load the diagnostic operating environment if the keyswitch is in the 'service' position.

Disclosed anonymously.

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