Browse Prior Art Database

Transient Program Code

IP.com Disclosure Number: IPCOM000119725D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Bealkowski, R: AUTHOR

Abstract

This article describes a technique which allows transient read-only memory (ROM) space in a computer system to be reclaimed so that other adapter cards can use it.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 67% of the total text.

Transient Program Code

      This article describes a technique which allows transient
read-only memory (ROM) space in a computer system to be reclaimed so
that other adapter cards can use it.

      In computer systems, adapter cards may have on-board ROM for
program code.  In some cases this ROM is required only once, during
system initialization.  The address space for feature card ROM is
C0000 hex through DFFFF hex.  Each feature ROM must be assigned a
unique address range to avoid conflicts.  The ROM for a feature card
may contain code for power-on self-test (POST), compatibility basic
input output system (CBIOS), and advanced BIOS (ABIOS).  In cases
where the ROM contains the BIOS routines, the ROM must remain present
in the address space.  However, if the ROM is only used for POST,
which could include some initialization, the ROM need only be present
during POST execution.  The technique disclosed herein allows the ROM
to be present when required for POST, then removed to allow the ROM
address space to be reclaimed.

      The method of this disclosure to reclaim ROM address space is
shown in the flowchart of the drawing.  This implementation utilizes
a ROM scan during the programmable option select (POS) phase of POST.
When the channel is reset, all the adapter cards are disabled.  Each
card slot is then placed into the set-up mode and the correct POS
data is programmed into the adapter from system non-volatile memory.
Once the POS data is progr...