Apparatus for protecting storage blocks from being accessed by unwanted I/O programs using I/O program keys and I/O storage keys having M number of bits
US5787309A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1996 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | May 23, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1466
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Main storage access protection against unwanted I/O accesses in storage blocks/page frames independent of any protection provided against unwanted CPU accesses. I/O programs are each assigned an I/O program key which is matched against an I/O storage key selected from an I/O storage protection array used only for protecting blocks from accesses by I/O programs, but not from any accesses by CPU programs. The address of each storage access request by an I/O program selects a key entry in the array containing the I/O storage key used in the comparison with the I/O program key. Each entry in the I/O storage array may also contain a second I/O storage key which may be either a one-bit type as described and claimed in application Ser. No. 08/652,197 or a two-bit type as described and claimed in application Ser. No. 08/652,079, both applications of which were filed on the same day as this application and assigned to the same assignee. CPU storage protection array is not required for I/O storage protection, but CPU storage protection may be added for protecting storage blocks against unwanted accesses by CPU programs. Either real or virtual CPU storage key protection may be added as compat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.