Browse Prior Art Database

Hard Disk Cache Alterations for Digital Versatile/Video Disks

IP.com Disclosure Number: IPCOM000118545D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Dewey, DW: AUTHOR

Abstract

Disclosed are alterations to a system that performs hard disk caching to improve access to Compact Disk-Read Only Memory (CD-ROM) drives to be used for accessing DVD-RAM drives. The hard disk caching system algorithm is altered based on the Digital Versatile/Video Disk (DVD) low level format.

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Hard Disk Cache Alterations for Digital Versatile/Video Disks

      Disclosed are alterations to a system that performs hard disk
caching to improve access to Compact Disk-Read Only Memory (CD-ROM)
drives to be used for accessing DVD-RAM drives.  The hard disk
caching system algorithm is altered based on the Digital
Versatile/Video Disk (DVD) low level format.

      Data on DVD disks is stored in one or more sessions.  Within
each session one or more fixed size recording units are present.
Each recording unit has a fixed number of logical blocks.  The file
system works with logical blocks and is unaware of the underlying
structures on  the media used to by the drive to record the blocks.
Updates to a block  involve updating the entire record unit.  This
introduces a new data integrity exposure existing software systems do
not address.  Namely, that a failure in writing a logical block may
loose data already written in other logical blocks.  This results
from the use of a record  unit containing multiple logical blocks and
the Error Correction Code (ECC) for all the blocks in that unit.

      This method proposes using an altered hard disk cache that
takes into account the record unit size.  The use of hard disk caches
with existing Compact Disk (CD) devices for performance has become
common and can be used to increase the performance of DVD-RAM drives
when available.  By altering the cache page frames of the hard disk
cache to match record unit size...