Browse Prior Art Database

Method of Dynamically Allocating Shared Memory

IP.com Disclosure Number: IPCOM000100963D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 111K

Publishing Venue

IBM

Related People

Geisler, DR: AUTHOR [+3]

Abstract

A technique is described whereby computer random-access memory is dynamically allocated upon demand for the purpose of sharing information between independent logical identifications residing on a feature read-only memory device.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method of Dynamically Allocating Shared Memory

       A technique is described whereby computer random-access
memory is dynamically allocated upon demand for the purpose of
sharing information between independent logical identifications
residing on a feature read-only memory device.

      Typically, logical identifications (LIDs) are independent
processes that may or may not share a common hardware resource.
Operations of a shared resource by one process require that the
state(s) of other processes with respect to the shared resource be
known for successful completion of a shared task.  Generally, systems
utilizing features with advanced basic input output system (ABIOS)
support, as used in a personal computer system, use a read-only
memory (ROM) which is located on the feature and not with the system
planar ABIOS.  However, there are no existing provisions for
independent LIDs residing on a feature ROM to dynamically request
memory for the purposes of sharing.  The concept described herein
provides a method to accomplish this sharing process during ABIOS
initialization.

      To share memory between the disk LIDs, the internal ABIOS
internal device ID device block (DB) located at LID 2 was chosen as
the link.  Henceforth, LID 2 will be referred to as the shared LID.
According to ABOIS architecture, the shared LID always exists.
However, it has a pre-defined DB initialized by the system planar
ROM.  The three steps to initialize ABIOS are as follows:
       1. System device count build.
       2. Initialization table build.
       3. DB and function transfer table initialization.

      In Step 1, the operating system establishes the number of LIDs
that are required to support the system configuration by calling
ABIOS.

      In Step 2, ABIOS returns its memory requirements for each type
of LID.  This includes the amount of memory required for the DB.
When disk ABIOS gains control during this step, it searches the
existing initialization table entries for the internal ABIOS device
ID.  When the internal ABIOS device ID is located, disk ABIOS
increases the value of the DB length field by the amount required.

      In Step 3, the DB and function transfer tables for each LID are
initialized.  During this step, the disk ABIOS locates the internal
ABIOS DB through the common data area (CDA) and increases its length.
However, this is not a trivial task since the DB has...