Browse Prior Art Database

Use of Service Mode for IPL ROM Function Execution

IP.com Disclosure Number: IPCOM000119409D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 35K

Publishing Venue

IBM

Related People

Benignus, D: AUTHOR [+4]

Abstract

Disclosed is the method for enhancing the Initial Program Load (IPL) function by providing Service mode to allow exhaustive machine testing beyond normal IPL function. When a system is powered on or reset, IPL code residing in ROM executes and loads a software program commonly called the boot program.

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Use of Service Mode for IPL ROM Function Execution

      Disclosed is the method for enhancing the Initial Program Load
(IPL) function by providing Service mode to allow exhaustive machine
testing beyond normal IPL function.  When a system is powered on or
reset, IPL code residing in ROM executes and loads a software program
commonly called the boot program.

      The IPL code determines the location of the boot program from
data in an IPL boot record. An IPL boot record resides at a known
location on an IPL device and contains the following:
1) IPL boot record identifier for a particular system.
2) The IPL device characteristics.
3) A boot program description; such as the location of the boot code
on the IPL device, its length and entry point.

      Most systems are concerned with the time it takes to IPL.  For
systems that have a switch that allows a user to IPL in Normal mode
or Service mode, some of the functions to be tested or run can be
made to run in Service mode only, thus saving time in Normal IPL
mode. On the other hand, if a user wants all functional tests to be
run, then the IPL from Service mode can be selected.  Examples of
function that can be included in the Service mode are:
1) IPLing from media that contains diagnostics such as diskette or CD
ROM.
2) More exhaustive tests such as IO Controller, planar, memory
testing, etc.

      Disclosed anonymously.