James Perchik

53136284, May 17, 1994

Dec 30, 1991

7/816350

Noah R. Mendelsohn - Arlington MA
James Perchik - Cambridge MA
Thomas R. Hancock - Somerville MA

International Business Machines Corporation - Armonk NY

G06F 1100

395575

Apparatus is described for component replacement control in a data processing system, with each component being assigned a label that includes a component identifier and a replacement generation value. The apparatus includes a plurality of tables for redundantly storing replacement generation values for each component. The tables that store the replacement generation values are then updated to indicate the incremented replacement generation value for the new component. Circuitry then increments the replacement generation value assigned to a component identity that is replaced by a new component. The circuitry modifies the new component's label to indicate the incremented replacement generation value. When the system is subsequently started, the replacement generation values in each component's label are compared with the replacement generation values in the tables and wherever a match is not found, the component is rejected.

52010449, Apr 6, 1993

Apr 16, 1990

7/509853

Alexander H. Frey - Pasadena CA
Richard C. Mosteller - Sierra Madre CA
Joel M. Gould - Norwood MA
Noah R. Mendelsohn - Arlington MA
James Perchik - Cambridge MA

International Business Machines Corporation - Armonk NY

G06F 1500

395575

A data processing system includes both volatile and nonvolatile memories, user-inaccessible file control software and performs a method for recovering from a malfunction occurring during a file transaction that prevents accomplished microscopic transactions from being lost. The method comprises the steps of: providing a log file to maintain a record of file transactions which may span both the volatile and nonvolatile memories; recording in the portion of the log file in volatile memory, old and new data images which result during a file transaction; writing the old and new data images to a portion of the log file which is contained in nonvolatile memory, with the new data image being written after it is certain that the old data image is present in the nonvolatile memory; and in the event of a malfunction, employing the log file in nonvolatile memory to determine the status of a file transaction and rolling back the transaction in the event the malfunction occurred prior to its completion, and further assuring that all file system actions have actually occurred for transactions marked as completed.