Abstract: An apparatus, system, and method are disclosed for recalling a logical volume from a mountable media for use in a virtual tape server. The apparatus includes a receiving module, a queuing module, and an optimizer module. The receiving module receives recall requests for logical volumes stored in a mountable media such as a tape cartridge. The queuing module places the requests in a queue to be processed in turn. The optimizer module reorders the queue based on one or more optimization rules in order to process the recall requests more efficiently.

Abstract: With detection of a selected error event involving a data storage drive and data storage media, a subsystem attempts to move the media to another drive, and conduct a similar operation. The subsystem separately tracks successive error events of individual drives and individual media, wherein a complete successful operation breaks the chain of the successive error events; and upon the number of successive error events reaching a threshold, fails the data storage drive or the data storage media. Error events are categorized into: 1) error events before or during a mount of a media into a drive; and 2) error events after a successful mount of a media into a drive; and conducts the tracking, comparing and failing steps separately for each of the categories for the drives and the media.

Abstract: With detection of a selected error event involving a data storage drive and data storage media, a subsystem attempts to move the media to another drive, and conduct a similar operation. The subsystem separately tracks successive error events of individual drives and individual media, wherein a complete successful operation breaks the chain of the successive error events; and upon the number of successive error events reaching a threshold, fails the data storage drive or the data storage media. Error events are categorized into: 1) error events before or during a mount of a media into a drive, and 2) error events after a successful mount of a media into a drive; and conducts the tracking, comparing and falling steps separately for each of the categories for the drives and the media.

Abstract: An automated data storage library stores logical volumes, including logical volumes to be copied to a second library, in cache storage, and migrates logical volumes to physical media volumes stored on storage shelves. In response to a request for recalling one of the logical volumes to be copied to cache, a library controller first determines which physical media volume contains the requested migrated logical volume. The library controller identifies all of the logical volumes to be copied that are migrated and stored as stacked logical volumes on the physical media volume containing the requested migrated logical volume; selects up to “N” of the identified logical volumes, including the requested migrated logical volume; and may arrange a selection list of the selected logical volumes in a sequence in accordance with the order that the logical volumes are written on the physical media volume.

Abstract: Disclosed is a system, typically implemented in a storage controller, for extracting data from a device storing data in a first format, such as the count-key-data (CKD) format. The first format is comprised of a plurality of tracks. Each track has at least one data area and each data area is comprised of at least one addressable block of data. A request from a host system for an address of a block of data in a second data format, such as the Fixed Block Architecture (FBA) format, is received. The system calculates a byte displacement value for the requested address. A data area in a track in the device having a byte displacement value less than the byte displacement value for the requested address is located. A byte location offset is then determined by subtracting the byte displacement value for the located data area from the byte displacement value for the requested address. The system then determines a location in the located data area of a block of data at the byte location offset.

Abstract: The present invention reduces the delay in the completion of transferring data from a data channel to an input/output device and the time a host unit is released from performing the data transfer function. A time reduction is realized by monitoring the current data transfer between the data channel and a buffer device to establish a transfer rate. The transfer rate is used to anticipate and coordinate the transfer of the last bit of data from the data channel to coincide with the receipt of the data by the input/output (I/O) unit, effectively eliminating buffer device delay and allowing the host unit to be released from performing the data transfer. In the preferred embodiment, the transfer of the last bit of data by the data channel occurs at substantially the same time as the last bit of data is received by the I/O unit.