| 摘要 |
<p>The deleted dataset space release system provides facilities in a dynamically mapped virtual memory data storage subsystem (100) to immediately release the physical space occupied by a deleted dataset for use by the data storage subsystem (100) 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 (113) and on the data storage devices (122-125). 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 (100) 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 (11, 12). The data storage subsystem (100) thereby immediately receives an indication that the host processor (11, 12) is scratching a data file from the volume table of contents of a virtual volume. The data storage subsystem (100) can then concurrently scratch this data file from the virtual track directory (401) contained in the data storage subsystem (100) and thereby release the physical storage space occupied by this scratched data file.</p> |
