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:
May. 24, 1983
Filed:
Apr. 03, 1980
Hitachi, Ltd., Tokyo, JP;
Abstract
This data processing system includes a main memory which is shared by a plurality of central processor units (CPUs) which are also coupled in cascade in a closed circular path. Each CPU has a cache buffer memory and two sets of transfer registers for receiving and transmitting cancel request signals which identify cache data which is no longer valid. Each CPU's receiving register subsystem includes circuitry for invalidating cache buffer data which has been updated or rewritten in main memory by another CPU in the loop. Each CPU's transmitting register subsystem includes circuitry for inhibiting the transmittal of a cancel request signal if the next CPU in the circle is the same one which originated the particular cache invalidation signal. Circuitry is also provided for propagating a cancel request signal around the loop in opposite directions simultaneously.