Method for managing I/O buffers in shared storage by structuring buffer table having entries include storage keys for controlling accesses to the buffers
US5724551A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1996 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | May 23, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1475
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A program stored on a portable storage medium for transferring the program from/to a data processing system, including to or from a disk medium in the system. The program manages I/O buffers that use I/O storage protection key for protecting storage blocks (page frames) in a shared main storage against unwanted I/O accesses, but the I/O storage keys do not protect the storage blocks from an CP (central processor) accesses. CP key protection may optionally be provided to independently protect the same storage block against unwanted CP accesses. Processes initialize, and address I/O buffers used by I/O programs; each I/O buffer is comprised of a contiguous set of the blocks (page frames). The I/O keys are used independently of any CP keys, and both I/O and CP keys are required for protecting any block against unwanted accesses by both I/O and CP accesses. The I/O keys are supported by a hardware I/O storage key array when real (or absolute) addressing is used by I/O the programs. However, the CP keys may be, but need not be, supported by CP keys in a second hardware key array; since the CP storage keys instead may be supported as virtual CP keys in CP key fields in page table entries…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.