| 摘要 |
<p>This invention relates to the fetch protection of a critical area in the main storage of a data processing system. The critical area is a part of a main storage block protectable by a single storage protect key having a fetch protection field. …<??>To enable different fetch protections within a special storage block, fetch protect override controls are provided which partly override the normal operation of the storage protect key for a page located at a predetermined address. While fetch protection is set on for the page's storage block, the fetch protect override controls disable fetch protection for a portion of the page's addresses, e.g. addresses 0-2047. …<??>Override enablement is controlled by a fetch protect override control bit in a control register, e.g. bit 6 of control register 0.</p> |
