Deleted data file space release system for a dynamically mapped virtual data storage subsystem
US5193184A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1990 |
| Grant date | Mar 9, 1993 |
| Priority date | — |
| Expiry date | Jun 18, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0689
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The deleted dataset space release system provides facilities in a dynamically mapped virtual memory data storage subsystem to immediately release the physical space occupied by a deleted dataset for use by the data storage subsystem to store subsequently received data files. This system also provides data security by preventing the unauthorized access to the data of scratched data files, both in cache memory and on the data storage devices. The deleted dataset space release system utilizes a user exit in the host processor data file scratch routine to transmit information to the data storage subsystem indicative of the host processor data file scratch activity. Existing channel command words are used in a manner that is transparent to the host processor. The data storage subsystem thereby immediately receives an indication that the host processor is scratching a data file from the volume table of contents of a virtual volume. The data storage subsystem can then concurrently scratch this data file from the virtual track directory contained in the data storage subsystem and thereby release the physical storage space occupied by this scratched data file.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.