Method, system and program products for managing changed data of castout classes
US6230243A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1999 |
| Grant date | May 8, 2001 |
| Priority date | — |
| Expiry date | Feb 19, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0866
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Changed data of castout classes of a coupling facility cache are managed in order to be able to efficiently determine the age of the oldest changed data in the cache. A directory entry representing a changed datum is placed in a data structure corresponding to the castout class of the changed datum. The data structure includes an order queue ordered by timestamps and a process queue, having an ordered portion and an unordered portion. When the directory entry is to be added to the data structure, an attempt is first made to place the entry on the order queue. If the entry is not placed on the order queue within a predefined amount of time, then the entry is placed on the process queue, the order of which is maintained by background tasks. In order to return the oldest entry of the data structure, the smallest entry of the process queue is determined and that entry is then compared to the smallest entry of the order queue. The smaller of those two entries corresponds to the oldest entry for the castout class.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.