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.

Date of Patent:
Feb. 07, 1995

Filed:

Sep. 17, 1992
Applicant:
Inventors:

Glen A Brent, Red Hook, NY (US);

Casper A Scalzi, Poughkeepsie, NY (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ; G06F / ;
U.S. Cl.
CPC ...
395400 ; 380-4 ; 395575 ;
Abstract

Logical erasure is done for a virtual page unit of storage in a virtual-page-initialization process (even though the data content of a backing page frame is not physically erased). Pre-initialization controls are associated with each virtual page by a pre-initialization field in each page table entry (PTE). The pre-initialization controls operate differently for fetches and stores within the address translation process. Both fetches and stores test for a pre-initialization state in an F field in the PTE to control if and when any backing page frame can be accessed. While the F field bit is set to its pre-initialization state, no erasure writing is done in any backing page frame for a fetch or full-page store operation. An optional form identifier (form#) field is associated with the pre-initialization state field. The form# field content identifies one of plural form functions or form page frames. Each fetch-only request (occurring prior to a first store to the virtual page) is diverted to a form PF to assure that no prior data in an assigned page frame can be fetched by the user, even though no physical erasure has been done to the contents of any assigned backing page frame. No backing PF needs to be assigned for a fetch-only operation, for which there is no page fault interruption.


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