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:
Dec. 03, 1991
Filed:
Jun. 23, 1989
Robert M Supnik, Carlisle, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
It is desirable to bypass the defects within a cache memory so that a high percentage of the cache is usable; otherwise the entire chip containing the cache memory must be scrapped. Since VLSI chips with a small number of defects form a large proportion of the scrapped yield, rendering chips with a small number of defects usable greatly increases the production yield and reduces the cost of each chip. Therefore, a cache memory is provided wherein each memory location includes a bit which is set in response to a detected hardware defect. Preferably, each memory location in the cache is tested by error detecting software, which sets the defect bit in any memory location containing a defect. The defect bit is tested every time data is retrieved from each memory location, and a set defect bit prohibits further use of a defective memory location.