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. 07, 1999
Filed:
Jul. 06, 1994
Mark A Taylor, Cupertino, CA (US);
David J Garcia, San Jose, CA (US);
Paul A Duffy, Mountain View, CA (US);
Tandem Computers Incorporated, Cupertino, CA (US);
Abstract
A pair of substantially identical integrated circuit elements, in the form of microprocessors, are operated in response to the same instruction and data signals that are accessed from a memory by one of the integrated circuits. The accessed instruction and data signal are supplied, via a synchronous interface, to the second integrated circuit, which operates thinking that the supplied data and instruction signals were accessed by it in response to address and control signals. The states of the two integrated circuits are applied to comparator circuitry, both via buffered paths. The comparator circuitry is operated in response to control signals produced by the first integrated circuit to effect comparison on only those signals that are valid at any particular moment in time. Clock-synchronizing circuitry is included to ensure that predetermined state transitions of the clocks used to operate the first and second integrated circuit occur within a prescribed time period.