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Preemptive Loading of Most Frequently Used Cartridges in Integrated or Automated Cartridge Loaders

IP.com Disclosure Number: IPCOM000110527D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Thrall, JL: AUTHOR [+2]

Abstract

Automated libraries use robotically controlled accessor mechanisms to move cartridges between storage slots and devices. If the workload of a library is skewed, a small number of cartridges may be frequently accessed. This article advocated the preemptive loading of the Most Frequently Used (MFU) cartridges in device-attached cartridge loaders called Integrated Cartridge Loaders (ICLs) or Automated Cartridge Loaders (ACLs). These ICLs/ACLs hold a small number of cartridges adjacent to the respective devices, thus becoming a form of MFU cartridge cache. Queue time could be drastically reduced because the MFU cartridges could be serviced by multiple ICL/ACL servers in addition to the library's main robotic accessor.

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Preemptive Loading of Most Frequently Used Cartridges in Integrated or Automated Cartridge Loaders

       Automated libraries use robotically controlled accessor
mechanisms to move cartridges between storage slots and devices.  If
the workload of a library is skewed, a small number of cartridges may
be frequently accessed.  This article advocated the preemptive
loading of the Most Frequently Used (MFU) cartridges in
device-attached cartridge loaders called Integrated Cartridge Loaders
(ICLs) or Automated Cartridge Loaders (ACLs).  These ICLs/ACLs hold a
small number of cartridges adjacent to the respective devices, thus
becoming a form of MFU cartridge cache.  Queue time could be
drastically reduced because the MFU cartridges could be serviced by
multiple ICL/ACL servers in addition to the library's main robotic
accessor.

      With the use of ICLs or ACLs with a random access capability,
MFU cartridges may be cached at the devices during periods of library
quiescence.  Examples of such MFU cartridges could be cartridges
typically accessed at a particular time, such as at the beginning of
the day or shift, or simply the cartridges which are most frequently
mounted.

      A usage pattern which could also benefit from the ICLs/ACLs
would be recently dismounted cartridges, as an appreciable number of
recently dismounted cartridges are soon remounted.  A selectable
timeout parameter with a default value of 1 hour could be used for
retaining dismounted cartridges in the respective ICL/ACL before the
main accessor would place that cartridge in a storage slot.  If an
ICL/ACL became...