Browse Prior Art Database

User-Controlled Media Directory Commitment

IP.com Disclosure Number: IPCOM000102343D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 82K

Publishing Venue

IBM

Related People

Bjork, TA: AUTHOR [+5]

Abstract

On WORM (Write Once Read Many) media, to avoid wasting directory space, it is desirable to cache directory updates until a complete media sector is filled. But when caching this data, there is an exposure to losing the saved data due to a failure of the caching device. A technique described here provides the user with the flexibility to control the commitment of directory data to WORM media to minimize either the risk of data loss or the amount of media space wasted.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

User-Controlled Media Directory Commitment

       On WORM (Write Once Read Many) media, to avoid wasting
directory space, it is desirable to cache directory updates until a
complete media sector is filled.  But when caching this data, there
is an exposure to losing the saved data due to a failure of the
caching device.  A technique described here provides the user with
the flexibility to control the commitment of directory data to WORM
media to minimize either the risk of data loss or the amount of media
space wasted.

      This method of controlling the risk exposure of the directory
data starts by adding a user-specified "file creation limit".  This
limit is specified for each volume separately as the volume is placed
in the library.  Each time a new file is added to a volume, a count
is increased. When the count reaches the user specified limit, all
directory data which has been cached will be written on the media.
Directory data will continue to accumulate normally until the limit
is reached.  That is, any full block of directory data will be
written, and any partially full blocks will be saved.  If the user
specifies a very high limit, a "natural" limit dictated by the block
size will eventually be reached, and directory data will be written
at approximately the rate it is created.  On the other hand, the user
could specify writing data after each new file is added to the media.
This is the most expensive in terms of media space, but it completely
elimin...