Browse Prior Art Database

Determination of Latest Read-Only Memory on Identical Adapters in IBM Ps/2 Computers

IP.com Disclosure Number: IPCOM000034747D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Einkauf, MA: AUTHOR

Abstract

Disclosed is a method which provides for the automatic determination of the most recent ROM (Read-Only Memory) among ROMs resident on identical adapters installed in an IBM Personal System/2* computer. This method also provides the freeing of ROM space assigned to those ROMs not determined to be the most recent. The IBM Personal System/2 computer features a mechanism by which installed adapters can initialize themselves during computer Power-On Self Test (POST). This mechanism is called ROM Scan. During ROM Scan, computer POST reads data at predetermined address ranges to determine if there is an adapter ROM present and, if so, passes control to that ROM. There are 16 such predetermined address ranges, or ROM "spaces", so there may be multiple adapters, each with its own unique ROM installed in the computer.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 55% of the total text.

Page 1 of 2

Determination of Latest Read-Only Memory on Identical Adapters in IBM Ps/2 Computers

Disclosed is a method which provides for the automatic determination of the most recent ROM (Read-Only Memory) among ROMs resident on identical adapters installed in an IBM Personal System/2* computer. This method also provides the freeing of ROM space assigned to those ROMs not determined to be the most recent. The IBM Personal System/2 computer features a mechanism by which installed adapters can initialize themselves during computer Power-On Self Test (POST). This mechanism is called ROM Scan. During ROM Scan, computer POST reads data at predetermined address ranges to determine if there is an adapter ROM present and, if so, passes control to that ROM. There are 16 such predetermined address ranges, or ROM "spaces", so there may be multiple adapters, each with its own unique ROM installed in the computer. Identical adapters may also be installed in the computer, with each adapter containing its own ROM. However, since identical adapters can be initialized by identical code, it is not necessary to have unique ROM spaces defined for each identical adapter. Indeed, assigning unnecessary ROM spaces for identical adapters is a waste of computer resoures. However, using only one ROM to initialize identical adapters presents the problem of determining which adapter's ROM to use. Although the adapters are identical, their respective ROM code may not be. If over time, improvements are made to the ROM code (such as added features or fixed problems), the identical adapters may each contain different version ROMs. In the case that different versions of the ROM existed on the identical adapters, it is preferable for the latest (most recent) version to initialize all the adapters. The method disclosed here determines the proper ROM to be used. An overview of the computer ROM Scan is shown below. BEGIN ROM SCAN:

For ROM space=1 to 16

If valid ROM data found in ROM space

Then, Pass control to that ROM

Next ROM space

END ROM SCAN: When ROM Scan passes control to a ROM, the ROM executes the following process to dete...