Browse Prior Art Database

Self-Initiating Diagnostic Program Loader from Failed Initial Program Load I/O Device

IP.com Disclosure Number: IPCOM000120924D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Crandall, DR: AUTHOR [+2]

Abstract

This article describes a technique for automatically loading a debug handloop for an initial program load (IPL) device.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Self-Initiating Diagnostic Program Loader from Failed Initial Program
Load I/O Device

      This article describes a technique for automatically loading a
debug handloop for an initial program load (IPL) device.

      A customer service representative (CSR) often requires the use
of special diagnostic routines (sometimes called handloops) to cause
activity on selected I/O components within a failing microcomputer
system.  This activity is required to enable the CSR to probe suspect
circuitry for potential faults using an oscilloscope or probe to
measure in-circuit waveforms.

      If the IPL device is the failing device and the diagnostic
programs, map packages, and other debug tools cannot be loaded
because of the IPL failure, then previously the only debug tool was a
hand-entered program to cause the I/O device to be active as
described above.  Keying in the program required an optional
programmer's console and took as much as fifteen to twenty minutes to
key in and check. This was wasted time installing a tool before a
useful debug could take place.

      In the technique of this disclosure a system handloop is stored
in the IPL device microprogram as data and when an IPL failure is
detected by that microprogram, it automatically loads that diagnostic
handloop into specific locations in the system main storage where it
is ready for the CSR to start using.

      Disclosed anonymously.