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Browse Prior Art Database

Special Sector Size for Write-Once Disk Directories

IP.com Disclosure Number: IPCOM000099628D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 81K

Publishing Venue

IBM

Related People

Winarski, DJ: AUTHOR

Abstract

It is often desirable to sort files by their respective versions. When multiple versions of files are stored on write-once or WORM optical media, directory information cannot be overwritten to be updated or directory information cannot be gathered, sorted, and rewritten on the optical disk without using up valuable disk space and a lot of time.

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This is the abbreviated version, containing approximately 52% of the total text.

Special Sector Size for Write-Once Disk Directories

       It is often desirable to sort files by their respective
versions.  When multiple versions of files are stored on write-once
or WORM optical media, directory information cannot be overwritten to
be updated or directory information cannot be gathered, sorted, and
rewritten on the optical disk without using up valuable disk space
and a lot of time.

      This article describes a method which enhances the performance
of the retrieval of versions of files archived on hard-sectored,
write- once optical media.  This performance enhancement is obtained
by the adjacent writing of the directory entries of versions of
respective files in special directory mini-sectors.

      The means of obtaining this performance enhancement rests with
the fact that directory entries for files are typically very short in
length compared to the 1/2 KB or 1 KB hard-sector size available for
storing this information. Unfragmented files need a directory entry
only a few dozen bytes long to specify the location of the file on
the disk, the length of the file, the date and time written, and
version number of the file.  Typically, only one file entry is made
to a sector during a nonsequential write.  This means that usually
most of each directory sector goes unused.

      To make use of this situation of short directory entries and
the desire to write these entries adjacently for versions of
respective files, the directory area of the hard-sectored, write-once
disk is further parti...