Browse Prior Art Database

Non-Mechanical Shock Proofing of Mass Storage Subsystems

IP.com Disclosure Number: IPCOM000114039D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 143K

Publishing Venue

IBM

Related People

Osborn, NA: AUTHOR [+2]

Abstract

Described is an architectural implementation that provides a non-mechanical method of improving the shock resistance of mass storage subsystems, such as hard disk drives used in portable type computers. The technique makes use of the differences in allowable shocks for fixed disk drives, between operational and non-operational modes, so as to increase the shock characteristics of the subsystem.

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This is the abbreviated version, containing approximately 40% of the total text.

Non-Mechanical Shock Proofing of Mass Storage Subsystems

      Described is an architectural implementation that provides a
non-mechanical method of improving the shock resistance of mass
storage subsystems, such as hard disk drives used in portable type
computers.  The technique makes use of the differences in allowable
shocks for fixed disk drives, between operational and non-operational
modes, so as to increase the shock characteristics of the subsystem.

      Due to the environmental requirements of portable type
computers, such as the ability to withstand extreme forces, internal
mass storage devices have been of the non-rotating type, such as
flash memory modules.  The flash memory modules can be relatively
more expensive than rotating memory devices, but have high shock
characteristics.  The concept described herein provides a means
whereby a mass storage subsystem, such as the rotating fixed disk,
can be used in portable type computers and still meet the shock
resistance requirements of portable computers.

      The concept is not limited to a rotating fixed disk type of
drive, but includes devices, such as the following:
 o   Storage devices - fixed disk type.
 o   Control program code executing as part of a disk controller
    (firmware), or on the host processor (BIOS/device driver).
 o   Any additional resources, such as main memory utilized by
control
    program code to implement a mass storage function, such as cache
    memory.

      Typically, laptop and notebook types of computers are used in a
fixed location, such as on a table top, on a lap, or on aircraft tray
tables.  When this type of computer is to be moved, the units are
usually turned off, or placed in suspended mode, relocated and then
located onto a surface before operation is resumed.  However,
portable type computers are designed to be operational during harsher
conditions, such as used while in moving vehicles.  As a result, the
computer must be designed to withstand severe mechanical stresses.

      So as to increase mechanical stresses, the shock requirements
of the rotating fixed disk during operational and non-operational
modes is taken into account.  When the unit is in non-operational
mode, the shock limit is determined by the mechanical damage that can
occur to the mechanism.  However, while in operating mode, a much
lower shock threshold is determined by the damage that can occur to
data considerations, rather than to physical damage.

      The technique employed by the concept is to control the usage
of the fixed disks.  Storage caching is employed so as to minimize
the time that the fixed disk drive is in operation.  In other words,
the technique is to maximize the time that the fixed disk drive is
not operating, thereby enabling the fixed disk to withstand greater
mechanical stress.

      In order to minimize the time that the fixed disk is in
operation, memory is added to the fixed disk m...