公开(公告)号：WO1981000161A1

公开(公告)日：1981-01-22

申请号：PCT/US1980000820

申请日：1980-06-27

Applicant: NCR CORP

Inventor： NCR CORP ,  DAVISON A ,  LEWIS W

IPC: G06F13/00

CPC classification number: G06F12/04 ,  G06F11/1056 ,  G06F13/16

Abstract: A memory system (10) having a word-addressable memory (12, 14) and bit changing circuitry (35) for changing or updating individual bits within the data words stored in the memory. The memory includes a primary memory (12) and a copy memory (14). The copy memory (14) stores duplicates of the data words stored in the primary memory (12). The bit changing circuitry (35) receives a word having a bit to be changed from the copy memory (14) and returns the word, including the changed bit, to both the primary memory (12) and copy memory (14). The memory system may constitute a parity memory system in a data processor.