Abstract: The data storage system is connected to a local area network and includes a storage server that on a demand basis and/or on a periodically scheduled basis audits the activity on each volume of each data storage device that is connected to the network. Low priority data files are migrated via the network and the storage server to backend data storage media, and the directory resident in the data storage device is updated with a placeholder entry to indicate that this data file has been migrated to backend storage. When the processor requests this data file, the placeholder entry enables the storage server to recall the requested data file to the data storage device from which it originated.

Abstract: A solid-state cache memory subsystem configured to be used in conjunction with disk drives for prestaging of data in advance of its being called for by a host computer features a controller featuring means for establishing and maintaining precise correspondence between storage locations in the solid-state array and on the disk memory, for use in establishing a reoriented position on a disk in the event of error detection, and in order to determine when a predetermined quantity of data has been read from the disk into the cache in a staging operation.

Abstract: A method for detection of a sequential data stream which can be performed in a data storge subsystem without host computer intervention is disclosed featuring examination of the channel program processed during a read operation for signals indicative that the data is not part of a sequential data stream, for example, embedded seek instructions. If a particular channel program for does not contain such indications, the successive record or records may then be staged to a faster access memory device such as a solid-state cache. The invention is described in a plug-compatible, software-transparent configuration.

Abstract: A method for detection of a sequential data stream which can be performed without host computer intervention is disclosed featuring examination of a data record and channel program during read operations for signals indicative that the data is not part of a sequential data stream, for example, embedded seek instructions. If a particular sought for record does not contain such indications, the successive record or records may then be staged to a faster access memory device such as a solid-state cache. The invention is described in a plug-compatible, software-transparent configuration.