Abstract: In a computer-implemented process, a task requiring access to a database uses an object-oriented class to enable one database connection for the duration of the task, avoiding multiple and concurrent database connections, thus allowing a more efficient use of the database connection.

Abstract: In a computer system including a disk controller and a disk drive, the disk controller determines whether to issue a command to the disk drive by considering both a priority level associated with the command, and a pending workload of the disk drive.

Abstract: A method for deriving format data for a functional disk drive volume includes the following steps. Initially format data is written onto a reference functional disk drive volume. A reference functional volume format data structure is then established which associates reference functional volume functional track values with physical track addresses for each track of the functional volume for which the format data was written. Thereafter, when a command is received to format a new functional volume, a copy of the reference functional volume format data structure is derived. Then, when a write command, for example, directed to a track of the new functional volume is received, the copy of the reference functional volume format data structure is used to access a corresponding formatted track from the reference physical disk drive volume. If a write action is then performed on the corresponding formatted track, the updated track is then written back to a physical disk drive at a new location.

Abstract: The invention implements a method for enabling overlapped performance of data processing actions during data transfers between a DSS and a host processor. The DSS includes a state queue which holds a plurality of states, each state comprising a self-contained procedure which, upon execution, determines a readiness to execute of an associated task. The method initially determines an amount of available time during a data transfer wherein a front-end processor of the DSS would otherwise be idle. The method then causes the front-end processor to extract and execute a first state from the state queue during the data transfer, if available time during the data transfer exceeds or is equal to an estimated execution time of the first state. Then, if a task associated with the first state is found to be ready to execute, that task is listed on a task work queue for execution subsequent to the data transfer.

Abstract: A data storage system includes at least first, second and third virtual storage volumes, the second and third virtual storage volumes being remotely coupled as a PPRC pair to enable a mirroring of data therebetween. The storage system is responsive to a snapshot command from a host processor, to cause transfer of the directory of the first virtual storage volume to the second virtual storage volume. The storage system then invokes a PPRC mirroring procedure which (i) detects an unsynchronized condition between the second and third virtual storage volumes (upon transfer of the directory from the first virtual storage volume to the second virtual storage volume), and (ii) causes a transfer of data, pointed to by the transferred directory, to the third virtual storage volume, until the second and third virtual storage volumes are again in synchronism.