Abstract: An apparatus, program product and method of processing access requests for a direct access storage device utilize a “fair elevator” algorithm to schedule access requests from a plurality of requesters desiring access to a direct access storage device (DASD). In particular, a fair elevator algorithm arbitrates requests by taking into account both the requesters with which various requests are associated, as well as the relative positions of the data to be accessed on the DASD. By sorting access requests based upon both requester identity and DASD position, both multitasking performance and DASD throughput are improved in a balanced manner, thus improving overall system performance.

Abstract: A method for recovering a computer system from a loadsource direct access storage device located at a remote location. In accordance with the method and system of the present invention, after a catastrophic damage and the installation of a local loadsource direct access storage device, an indicator within the local loadsource direct access storage device is set such that the local loadsource direct access storage device cannot be utilized for initial program load. Thereafter, the contents of the entire loadsource direct access storage device located at a remote location are copied to the replacement local loadsource direct access storage device. The indicator within the replacement local loadsource direct access storage device is reset such that the replacement local loadsource direct access storage device can be utilized for initial program load again. Finally, an initial program load is performed from the replacement local loadsource direct access storage device.

Abstract: Method and apparatus for managing data on DASD units to improve system performance comprises monitoring portions of data on a plurality of DASD units to determine the times the data is accessed within a given time period, and characterizing accessed data portions of a DASD unit as HOT and COLD data. The DASD units are monitored to determine the number of times each unit is accessed within a time period to develop utilization factors reflective of the number of times the DASD unit is accessed during the time period. HOT and COLD data is moved between DASD units based on the utilization factors of the DASD units.