Browse Prior Art Database

Method and System for Allowing Customer Access to Spare Capacity in a No-ID Disk Drive

IP.com Disclosure Number: IPCOM000115821D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Dobbek, J: AUTHOR

Abstract

With adaptive formatting schemes in disk drives there is a strong possibility of leaving contiguous quantities of sectors unused (wasted) in most of the files that leave the factory. This invention allows access to this capacity, essentially creating a variable length drive based upon the total capacity and the "factory found" defective sectors.

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Method and System for Allowing Customer Access to Spare Capacity
in a No-ID Disk Drive

      With adaptive formatting schemes in disk drives there is a
strong possibility of leaving contiguous quantities of sectors unused
(wasted) in most of the files that leave the factory.  This invention
allows access to this capacity,  essentially creating a variable
length drive based upon the total capacity and the "factory found"
defective sectors.

      In general, disk drives are sold with a "fixed" storage
capability.  This "fixed" capacity is normally the total capacity
minus the "system required space", minus the space held for
reassigns.  In some files this reassign area may be very small and in
some files this number could be as high as 2% or 3%.  The system
makes this number as large as required to meet manufacturing yields.
Once the file leaves the factory almost all of this space is wasted,
never to be used.  The primary method of this advance is to allow the
customer access to this data capacity if needed.  This could be as
simple as allowing the maximum Logical Block Address (LBA) to expand
to meet the requirements and still be under the "true" capacity of
the drive.  A mode page command would be used for this or any other
method.  Drives which do not meet the target defect rates and
therefore have below the desired capacity could be sold as such and
use this method in reverse.