Browse Prior Art Database

Dynamically Loadable Basic Input Output System

IP.com Disclosure Number: IPCOM000114798D
Original Publication Date: 1995-Feb-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 4 page(s) / 130K

Publishing Venue

IBM

Related People

Crump, D: AUTHOR [+4]

Abstract

Disclosed is a mechanism by which the firmware in a personal computer can be upgraded without the added cost of a flash memory or the complexity of changing a chip. The updated code can be stored in a reserved area on the hard disk. The existing firmware can check for the existence of an upgrade and load it into shadow memory very early in the boot process. The system can then be restarted executing the updated code from the shadow memory.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 42% of the total text.

Dynamically Loadable Basic Input Output System

      Disclosed is a mechanism by which the firmware in a personal
computer can be upgraded without the added cost of a flash memory or
the complexity of changing a chip.  The updated code can be stored in
a reserved area on the hard disk.  The existing firmware can check
for the existence of an upgrade and load it into shadow memory very
early in the boot process.  The system can then be restarted
executing the updated code from the shadow memory.

      Ever since the beginning of the Personal Computer, the Basic
Input Output System (BIOS) firmware has been getting more and more
complex.  As the complexity grows, the exposure of shipping BIOS
errors to the field grows.  End users are demanding the flexibility
to be able to update their system BIOS when problems are found by the
Original Equipment Manufacture (OEM).  To address this problem and
help with manufacturing lead times, OEMs have started using flash
memory to store the system BIOS.  Flash provides the ability for
either the OEM or the customer to update or upgrade the system BIOS
functions at a later date.

      One of the biggest problems with flash has been the additional
cost of using flash memory.  For a 128K part the additional cost of
flash over typical EPROM is approx.  $2-3 per system.  What is
needed, is another solution to provide upgradeable BIOS without the
additional cost associated with flash memory.  Other solutions of
having only a boot strap ROM that loads the system BIOS into memory
from the hardfile suffer from the problem of being tied to a
particular hardfile.  When the hardfile has a problem, the system
will not work at all.  This solution attempts to give the best of
both methods.

      It was decided, that having only a system boot strap ROM with
the BIOS on the hardfile was not acceptable since it made the system
dependent upon a particular hardfile.  We needed to ship a fully
functional system BIOS on the planar so that other hardfiles could be
used by the user.  In order to solve the problem of providing a low
cost BIOS upgrade, it was necessary to solve several problems.
  1.  The provision for a low-cost non-volatile storage area was
       needed.
  2.  The integrity of the BIOS upgrade must be insured and
maintained.
  3.  A way was needed to use the existing system BIOS in EPROM to
boot
       strap the new BIOS upgrade image into the system and transfer
       control to it.

      The cheapest low cost non-volatile storage is the existing
hardfile.  However, if the hardfile were used as a storage or for
BIOS upgrade, then some storage mechanism need to be developed that
would allow the BIOS to store and access the information.  The
storage mechanism needed to provide integrity of the data so that the
data would not be accidentally modified.  A special area on the
system hardfile was developed to store a variety of hardware system
informat...