Browse Prior Art Database

Three Card Loader for Operating System Initial Program Load Text

IP.com Disclosure Number: IPCOM000080551D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Orlinski, JF: AUTHOR

Abstract

Testing new or changed Initial Program Load (IPL) text previously required using an Operating System (OS) Utility Program to place the assembled object deck for IPL on a disk pack, as part of the Utility Program analyze function. Then track 0 of this analyzed pack had to be copied by the utility dump function to an OS SYSRES pack. This procedure provides a quick bypass to this lengthy procedure.

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Three Card Loader for Operating System Initial Program Load Text

Testing new or changed Initial Program Load (IPL) text previously required using an Operating System (OS) Utility Program to place the assembled object deck for IPL on a disk pack, as part of the Utility Program analyze function. Then track 0 of this analyzed pack had to be copied by the utility dump function to an OS SYSRES pack. This procedure provides a quick bypass to this lengthy procedure.

A lot of time could be saved if there was a way to load an IPL object deck directly into core and pass control to it. On two other stand-alone hexadecimal (hex) loaders, several modifications were needed to apply to OS IPL text. First, the address where the hex loader program executes in core had to be high enough so IPL text would not overlay it. Second, there needed to be a way to stop at the end of execution of the hex loader, so low core changes could be made to indicate the address of the disk drive where the system residence volume was mounted, and to indicate which nucleus was to be loaded.

The first card of the hex loader contains the IPL bootstrap records (a Program Status Word (PSW) and 2 read Channel Command Words (CCW's)). The other two cards contain the executable code of the hex loader. The hex loader reads cards from the card reader, loads text cards into core at their indicated addresses, finds where to start execution of IPL text from the end card, and ignores all other types of cards. This...