Abstract: A method and system in accordance with the present invention provides additional addressable space on a disk for use by a host processor using a virtual data storage subsystem. The method and system includes defining at least one of a plurality of extended image devices on a disk and requesting an instant image to be addressed to an extended image device utilizing channel command words by a host processor. The method and system also includes reading the instant image utilizing commands, such as channel command words or common descriptor blocks, by the host processor. In a method and system in accordance with the present invention, a plurality of extended image devices are defined as extensions of a primary functional device. Data may be transferred between at least one of the plurality of extended images and the primary functional device, or between at least one of the plurality of extended image devices and another of the plurality of extended image devices.

Abstract: The MVS device backup system functions to enable the data processor to manage the device backup function of a disk data storage subsystem in a manner that minimizes the expenditure of data processor resources. This is accomplished by the MVS device backup system determining the source device volume on the data storage subsystem, the target device volume on the data storage subsystem and identifying the extent of both. The MVS device backup system then transmits data to the data storage subsystem, representative of the assignment of DASD full tracks from the source device location on the data storage subsystem as well as DASD full tracks from the target (backup) device location on the data storage subsystem. The data processor based MVS device backup system then uses ECAM channel programs to instruct the data storage subsystem to perform the device backup operation using snapshot track pointer copy operations.

Abstract: The DASD file system copy system functions to enable the data processor to manage the data file copy function of a disk data storage subsystem in a manner that minimizes the expenditure of data processor resources. This is accomplished by the DASD file system copy system determining the source location on the data storage subsystem, the target location on the data storage subsystem and identifying the extents of both. The DASD file system copy system then transmits data to the data storage subsystem, representative of the assignment of DASD full tracks from the source location on the data storage subsystem as well as DASD full tracks from the target location on the data storage subsystem. The data processor based DASD file system copy system then uses ECAM channel programs to instruct the data storage subsystem to perform the data file copy operation using snapshot track pointer copy operations.

Abstract: The write notification during copy system functions to enable the data processor to manage the data file copy function of a disk data storage subsystem in a manner that minimizes the expenditure of data processor resources. This is accomplished by the write notification during copy system determining the source volume on the data storage subsystem, the target volume on the data storage subsystem and identifying the extents of both. The write notification during copy system then transmits data to the data storage subsystem, representative of the assignment of DASD full tracks from the source location on the data storage subsystem as well as DASD full tracks from the target location on the data storage subsystem. The data processor based write notification during copy system then uses ECAM channel programs to instruct the data storage subsystem to perform the data file copy operation using snapshot track pointer copy operations.