Chingshun J Cheng

US Patent:

51558440, Oct 13, 1992

Filed:

Feb 14, 1990

Appl. No.:

7/479911

Inventors:

Chingshun Cheng - Austin TX
Scott L. Porter - Austin TX
William C. Richardson - Round Rock TX
Paul J. Roy - Round Rock TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 2900

US Classification:

395575

Abstract:

A system and method is provided for testing a computer system main memory during system startup. An initial block of memory is tested and marked as valid or invalid during a startup sequence, with the remaining system memory initially marked as bad. An operating system and applications can be loaded into the initial block and operate normally, and a concurrent process is invoked to test the remaining system memory. This allows the remaining system memory to be tested and marked as valid during normal system operation.

US Patent:

53575210, Oct 18, 1994

Filed:

Mar 10, 1993

Appl. No.:

8/033066

Inventors:

Chingshun Cheng - Austin TX
Paul J. Roy - Round Rock TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 2900

US Classification:

371 213

Abstract:

A method for testing directly addressable memory in a computer system uses address sensitive test data. When a memory error occurs, or when an initial testing of the memory indicates an error, the affected locations are retested with selected address sensitive memory test patterns. Proper address sensitive pattern selection allows all of the data bits, ECC data bits and address parity bits to be tested.