公开(公告)号：US3588830A

公开(公告)日：1971-06-28

申请号：US3588830D

申请日：1968-01-17

Applicant: IBM

Inventor： DUDA WILLIAM J ,  TERMAN LEWIS M

IPC: G11C29/00 ,  G06F11/00

CPC classification number: G11C29/70

Abstract: A SYSTEM IS SET FORTH FOR UTILIZING BATCH FABRICATED MEMORIES DESPITE THE PRESENCE OF PERMANENTLY UNUSABLE BITS IN SUCH MEMORIES. IN ADDITION TO A MAIN BULK MEMORY, THERE IS PROVIDED AN ERROR CORRECTION MEMORY WHICH STORES THE LOCATION AND CORRECT INFORMATION TO BE SUBSTITUTED FOR EACH BAD BIT IN THE MAIN BULK MEMORY AND WHICH MAY BE MANUFACTURED BY THE SAME TECHNOLOGY EMPLOYED TO MAKE THE MAIN BULK MEMORY. WHEN THE BULK MEMORY IS ACCESSED, THE ERROR CORRECTION MEMORY IS ACCESSED SIMULTANEOUSLY. THE OUTPUT OF THE ERROR CORRECTING MEMORY IS SCANNED FOR AN INDICATION OF ONE OR MORE BAD BITS IN THE SIMULTANEOUSLY ACCESSED BULK MEMORY WORD. IF NO INDICATION IS FOUND, THE BULK MEMORY WORD IS CORRECT AS IT STANDS, IF ONE OR MORE INDICATIONS ARE FOUND, THE LOCATION OF THE BITS IN THE BULK MEMORY WORD AND THEIR CORRESPONDING CORRECT INFORMATION BITS ARE INSERTED INTO THE ACCESSED BULK MEMORY WORD.