Selecting a data unit candidate to be demoted to a backing store from a front store based upon thresholds individual to each of the data candidates
US5440686A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1993 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Dec 22, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/41
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A record media (optical disk) automatic library (back store) houses a plurality of record media for selective mounting in any one of a plurality of media drives (front store). Each record medium has one or more addressable recording surfaces termed data units. Record media currently mounted in said media drives may be replaced by other record media (demounted) only if the individual data unit has been idle (not accessed) for a time longer than a predetermined horizon time (demount eligibility threshold). If the current idle times for all mounted media are less than the respective horizon times, then no media can be demounted. Then, all proposed record media mounts are delayed until one of the currently mounted record media becomes eligible for demounting. If a plurality of mounted record media are eligible for demounting, then a least recently used one of the data units is demounted. The idle time of each mounted data unit is separately timed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.