System for storage protection from unintended I/O access using I/O protection key by providing no control by I/O key entries over access by CP entity
US5802397A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1996 |
| Grant date | Sep 1, 1998 |
| Priority date | — |
| Expiry date | May 23, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1475
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Protection against unwanted I/O accesses in main storage blocks/page frames independent of any storage protection provided against unwanted CPU accesses. An I/O protection array is used containing one-bit I/O keys used only for protecting which respectively protect associated blocks/page frames from unwanted accesses by I/O programs. Each one-bit I/O key is used to allow or disallow I/O accesses into an associated storage block. Any CPU access is not affected by the I/O storage key. No I/O program key is used and therefore no key compare operation is required. However, the embodiment is compatible with use of CPU storage protection using CPU storage keys in either real form in a CPU storage key array, or in virtual form in page table entries without using any CPU storage key array.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.