Browse Prior Art Database

System Control of Memory Refresh

IP.com Disclosure Number: IPCOM000083875D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

DiPilato, NM: AUTHOR

Abstract

Systems that employ dynamic memory technologies assure retention of the stored information by using periodic refresh. Periodic refresh, however, reduces the throughput of the system, due to the unavailability of the dynamic memory during the refresh time period. By using system control logic for memory refresh, part of this lost time can be recovered; allowing faster effective instruction execution and direct control of the refresh memory activity.

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System Control of Memory Refresh

Systems that employ dynamic memory technologies assure retention of the stored information by using periodic refresh. Periodic refresh, however, reduces the throughput of the system, due to the unavailability of the dynamic memory during the refresh time period. By using system control logic for memory refresh, part of this lost time can be recovered; allowing faster effective instruction execution and direct control of the refresh memory activity.

As shown, coded instructions are applied to the logic block A for determining, by decoding the instructions, when a refresh pulse should be generated and sent to memory. In a system where there is a mixture of short and long coded instructions, the refresh pulses are issued to memory during certain decoded short instructions. If this is done, the effective amount of time that the memory is available is increased. The word line counter B insures that only a given block of word lines in memory are refreshed during a given time interval. The time interval counter C insures that if a block of word lines are not refreshed, the remaining word line refresh pulses are sent to memory before any data is lost.

The counter reset logic D is used to reset the time interval counter C as follows: 1) If sufficient refresh pulses are sent to memory during a predetermined time interval, the word line counter B output resets the time interval counter C. 2) If the refresh pulses are insufficient, the time i...