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Anticipatory Mount of MFU Cartridge in an Automated Library

IP.com Disclosure Number: IPCOM000120782D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Winarski, DJ: AUTHOR

Abstract

Optical libraries can take several seconds to get a new disk mounted and spun-up. This article gives a menu-selectable means of mounting the MFU (Most Frequently Used) cartridges in anticipation of their being requested. The result is that the MFU disks will seem to usually be online, i.e., mounted.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 55% of the total text.

Anticipatory Mount of MFU Cartridge in an Automated Library

      Optical libraries can take several seconds to get a new
disk mounted and spun-up.  This article gives a menu-selectable means
of mounting the MFU (Most Frequently Used) cartridges in anticipation
of their being requested.  The result is that the MFU disks will seem
to usually be online, i.e., mounted.

      The cartridges in optical libraries can experience a skewed
access pattern.  If the access pattern is skewed so that there are a
few cartridges which are frequently accessed, one would want these
cartridges mounted as much as possible in order to provide online
access to these cartridges, i.e., access without delays for mount and
spin- up.

      Via a menu at the system level, the top "N" MFU cartridges
could be selected for anticipatory mounting.  The value set for "N"
could be up to the number of drives "D" in the library box.

      If a check of the list of the "N" MFU cartridges showed that
they were not all mounted in drives, the control unit of the library
would search for inactive drives.  Those drives inactive for more
than "T" seconds and not holding any of the "N" MFU cartridges would
be emptied and a cartridge from the list of the "N" MFU cartridges
would be mounted in anticipation of the next mount request.  The
value of time delay "T" would be set in the same menu where the
number "N" of the MFU cartridges was set.

      This decision making process would result i...