Donald Edward Lang

US Patent:

58600884, Jan 12, 1999

Filed:

Dec 6, 1996

Appl. No.:

8/761719

Inventors:

Michael T. Benhase - Tucson AZ
James Thomas Brady - San Jose CA
Damon W. Finney - San Jose CA
Michael Howard Hartung - Tucson AZ
Michael Anthony Ko - San Jose CA
Donald J. Lang - Cupertino CA
Jaishankar Moothedath Menon - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1202

US Classification:

711112

Abstract:

A method enables a host processor, which employs variable length (VL) records, to transparently communicate with disk storage which employs fixed length (FL) sectors for storage of the VL records. The method comprises the steps of: a) deriving a first control data structure for an update VL record, the first control data structure including information describing segments of the update VL record; b) determining an FL sector wherein an old VL record commences that corresponds to the update VL record; c) if the old VL record commences at other than a sector break of the FL sector, deriving a second control data structure for a portion of a prior VL record that immediately precedes the old VL record and a third control data structure for the old VL record; d) substituting in the third control data structure, information regarding update segments of the update VL record from the first control data structure; and recording in the FL sector determined in c), data indicated by the second control data structure and at least a portion of the update VL record, through use of the third control structure as altered in d).

US Patent:

58572139, Jan 5, 1999

Filed:

Dec 6, 1996

Appl. No.:

8/761639

Inventors:

Michael T. Benhase - Tucson AZ
James Thomas Brady - San Jose CA
Damon W. Finney - San Jose CA
Michael Howard Hartung - Tucson AZ
Michael Anthony Ko - San Jose CA
Donald J. Lang - Cupertino CA
Jaishankar Moothedath Menon - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1202

US Classification:

711112

Abstract:

A method enables a host processor, which employs variable length (VL) records, to communicate with disk storage which employs fixed length (FL) sectors for storage of the VL records. The method comprises the steps of: a) deriving a first control data structure for an update VL record, the first control data structure including information describing segments of the update VL record; b) determining a disk track that includes a FL sector wherein am old VL record commences that corresponds to the update VL record; c) reading each FL sector in the disk track and creating a control data structure which includes information describing each VL record stored in the disk track; d) substituting in a control data structure for the old VL record that corresponds to the update VL record, information regarding update data from the first control data structure; e) recording in the disk track, data indicated by each control data structure determined in steps c) and d); and f) if the old VL record ends at other than a sector break of a FL sector, reblocking VL records into FL sectors which are recorded thereafter on the disk track. The invention also enables a read action to be accomplished in one rotation of a disk even though it commences at a FL sector that is not at the beginning of a VL record to be accessed.