Browse Prior Art Database

Device ID Extensions in Post Error Logging

IP.com Disclosure Number: IPCOM000112891D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Randall, DL: AUTHOR [+3]

Abstract

Disclosed is the use of a unique device ID value of 255 to indicate that the actual ID of a device is greater than 255. This method provides an interface for logging error conditions between Power-On Self Test (POST) and the POST Error Processor, when such error conditions are detected in devices having actual IDs greater than 255. The POST error processor, which displays text messages specific to the error codes, has previously been operational only for devices with assigned IDs of 254 or less.

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This is the abbreviated version, containing approximately 57% of the total text.

Device ID Extensions in Post Error Logging

      Disclosed is the use of a unique device ID value of 255 to
indicate that the actual ID of a device is greater than 255.  This
method provides an interface for logging error conditions between
Power-On Self Test (POST) and the POST Error Processor, when such
error conditions are detected in devices having actual IDs greater
than 255.  The POST error processor, which displays text messages
specific to the error codes, has previously been operational only for
devices with assigned IDs of 254 or less.

      With this method, a unique device ID value of 255 is defined
along with an extension specified to the Basic Input Output Services
(BIOS) interrupt program interface.  This ID value triggers the BIOS
program interface to handle the higher device IDs.

      The Figure is a block diagram of the control flow for invoking
the BIOS/POST error logging program interface.  Registers are shown
in parentheses ().  In block 1, the device ID is assigned to the
device.  In block 2, a check is made to determine if the device ID is
greater than 255.  If the device ID is greater than 255, in block 3,
register (BH) is set to the value 255, and register (BL) is set to a
value which is equal to the actual ID value minus 255.  If the device
ID is not greater than 254, in block 4, register (BH) is set to the
value of the actual device ID, and register (BL) is set to the error
code for logging.  Then in block 5, regardless of...