Cynthia A Burns

US Patent:

56849737, Nov 4, 1997

Filed:

Aug 30, 1996

Appl. No.:

8/706175

Inventors:

Timothy J. Sullivan - Clinton MA
Cynthia J. Burns - Franklin MA
Albert T. Andrade - North Grafton MA
Ralph C. Frangioso - Franklin MA

Assignee:

Data General Corporation - Westboro MA

International Classification:

G06F 1200
G06F 1300

US Classification:

395405

Abstract:

An expandable memory system and a method for operating a memory system having a variable number of memory banks are described. The memory system can utilize a variable number of separately replaceable memory banks which can be implemented with memory element, such as dynamic random access memory chips, which are of differing speeds and or sizes. The memory system implements an interleaving of memory addresses among the memory banks as a function of the number of banks actually present so that successive memory accesses are not unnecessarily delayed by the recovery times of the memory elements. The memory system includes a programmable address decoder having a writable memory which provides bank address signals. Each of the banks includes a respective delay line for providing an output signal a respective presettable time after address signals are received by that bank for signalling to the host that data is ready to be transferred.