Method and apparatus for expansion, contraction, and reapportionment of structured external storage structures

• Main Authors: HELFFRICH; AUDREY ANN, DAHLEN; DENNIS JAMES, NICK; JEFFREY MARK, PALMER; STEWART LAUNDON, WILKINSON; WENDELL WILEY, KING; RICHARD PERVIN, ELKO; DAVID ARLEN
• Format: Patent
• Language: English
• Published: 13.10.1998
• Edition: 6
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

A method and apparatus for optimizing a data structure of an external data storage facility shared by a plurality of data processing systems, the data structure being allocated by a first allocation command which includes first allocation parameters based on an amount of storage space in the external data storage facility assigned for creation of the data structure and a composition of the data structure, includes a device for determining values of the first allocation parameters, to thereby determine a first composition of the data structure, a device for determining an actual usage of the data structure, to thereby determine a second composition of the data structure, a device for comparing the first composition of the data structure with the second composition of the data structure, and a device for issuing, based on an output from the comparing device, a second allocation command having second allocation parameters, to the data structure for reallocation thereof. The issuing device includes a device for adjusting the first composition of the data structure to the second composition, as storage space in the external data storage facility and processing cycles become available to execute the second allocation parameters. Until the second allocation parameters are achieved, the reallocation of the data structure remains pending and all processing commands are accepted and processed by the external data storage facility.