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. 15, 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
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.