Method for managing I/O buffers in shared storage by structuring buffer table having entries including storage keys for controlling accesses to the buffers
US5809546A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1996 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | May 23, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1475
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
I/O protection key processes for protecting storage blocks (page frames) in a shared main storage against unwanted I/O accesses. Independent CP (central processor) key protection may optionally be provided to protect the same storage against unwanted CP accesses. Processes are included for initializing, and addressing I/O buffers used by the I/O programs; each I/O buffer is comprised of a contiguous set of the blocks (page frames). The I/O keys may be used independently of any CP keys provided for protecting the same blocks against unwanted accesses by any CP in the system. The I/O keys must be supported by a hardware I/O storage array when only real (or absolute) addressing is used by I/O programs. However, the CP keys may be supported by either real CP keys in a second hardware key array; or alternatively the CP keys may be provided as virtual CP keys in a field in each page table entry (which is used for translating CP virtual addresses to CP real addresses). The separate I/O and CPU access protection functions may each include any or all of: write protection, read protection, and storage key protection for page frames.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.