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Browse Prior Art Database

Method of Maintaining Data Integrity in Portable Computer Systems

IP.com Disclosure Number: IPCOM000113755D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 136K

Publishing Venue

IBM

Related People

Osborn, NA: AUTHOR [+2]

Abstract

Described is an architectural implementation to provide a method of maintaining data integrity in portable computer systems. The implementation is designed to enable a portable computer, which includes a mass storage facility, such as a rotating disks, to operate under severe mechanical stress.

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

Method of Maintaining Data Integrity in Portable Computer Systems

      Described is an architectural implementation to provide a
method of maintaining data integrity in portable computer systems.
The implementation is designed to enable a portable computer, which
includes a mass storage facility, such as a rotating disks, to
operate under severe mechanical stress.

      Typically, portable computer systems, as opposed to most laptop
and notebook class of Personal Computers (PCs), may be in motion
while operating.  In this type of environment, the portable computer
must operate under severe mechanical stress.  Generally, fixed disk
drives were not capable of withstanding such extreme forces.  As a
result, prior art designs have utilized costly non-rotating
semiconductor memory devices, such as "Flash" Electronically Erasable
Programmable Read Only Memory (EEPROM) devices as the method of
storage.

      The concept described herein provides a means whereby a mass
storage subsystem, such as fixed disk drives, are used in such a way
as to increase the shock capability of a subsystem.  This enables a
shock resistant portable computer to be used, at significantly less
cost, as compared to prior art semiconductor memory based
implementations.  The mass storage subsystem design is not limited to
rotating fixed disk drives, but rather includes the following:
  o  A storage device which may be a fixed disk drive.
  o  A control program code executing, as part of a disk drive
     controller (firmware) or on the host processor Basic
Input/Output
     System (BIOS) device driver.
  o  Any additional resources, such as main memory, to be utilized by
     the control program code to implement a mass storage function,
     such as cache memory.

      Typically, laptop and notebook computers are used in a fixed
location, such as on a table top, or a lap or aircraft tray table.

When this type of computer is moved, it is turned OFF, or placed in
suspended mode, then relocated and placed on such a surface for
operation.  Thinkpad types of computers are generally designed to be
used while in motion, generally in an operator's arms, or mounted
onto a moving object.

      When a portable computer is used in motion type of
applications, the computer's subsystems must be able to with stand
severe mechanical stresses that are far beyond those required for
laptop/notebook type of computers.  To obtain operations in severe
environments, designers have utilized non-volatile memory devices,
such as "Flash" EEPROM's.  As compared to disk drives, the EEPROMS
are significantly more costly per megabyte of storage.  The fixed
disk storage approach is considered fragile as compared to
semiconductor types of storage.  Typically, shock specifications for
fixed disk drives are limited to 10 to 50 Gs while operating, while
semiconductor types of memory can withstand forces in excess of 1000
Gs.

      The concepts aim i...