The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 01, 1998
Filed:
May. 23, 1996
Paul Gregory Greenstein, Croton-on-Hudson, NY (US);
Richard Roland Guyette, LaGrangeville, NY (US);
John Ted Rodell, Wapplingers Falls, NY (US);
International Business Machines Corporation, Armonk, NY (US);
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.