Storage Technology Corporation

Mogens H Pedersen

George A Rudeseal

Jay S Belsan

Charles Allen Milligan

Patrick James Tomsula

Henry S Ludlam

Robert J Raicer

Charles Patrick Schafer

Jeffrey Steven Laughlin

John F Kitchen

Barbara L Steele

This file server system appears to the host computer to be a plurality of data storage devices which are directly addressable by the host computer using the native data management and access structures of the host computer. The file server however is an intelligent data storage subsystem that defines, manages and accesses synchronized sets of data and maintains these synchronized sets of data external from the host computer system's data management facilities in a manner that is completely transparent to the host computer. This is accomplished by the use of the snapshot application data group that extends the traditional sequential data set processing concept of generation data groups.

File server having snapshot application data groups

The deleted dataset space release system provides facilities in a dynamically mapped virtual memory data storage subsystem to immediately release the physical space occupied by a deleted dataset for use by the data storage subsystem to store subsequently received data files. This system also provides data security by preventing the unauthorized access to the data of scratched data files, both in cache memory and on the data storage devices. The deleted dataset space release system utilizes a user exit in the host processor data file scratch routine to transmit information to the data storage subsystem indicative of the host processor data file scratch activity. Existing channel command words are used in a manner that is transparent to the host processor. The data storage subsystem thereby immediately receives an indication that the host processor is scratching a data file from the volume table of contents of a virtual volume. The data storage subsystem can then concurrently scratch this data file from the virtual track directory contained in the data storage subsystem and thereby release the physical storage space occupied by this scratched data file.

Deleted data file space release system for a dynamically mapped virtual

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Longmont, CO, United States of America

Mogens H Pedersen