Method and apparatus for making independent data copies in a data processing system

摘要

A method for copying a data file from a source device to a destination device. In response to a copy command from a requesting host application identifying the source file and the storage locations in a destination, an extents track is formed to establish an environment in which the file will be copied. The calling system receives an immediate response that the copy operation is complete even though no data has been copied. Application programs may access the file in either the source or the destination. A copy program transfers the file on a track-by-track basis to the destination storage locations. Procedures assure that any data access to a particular track in either the source or destination by any application prior to the transfer of that track are accommodated to maintain data integrity.