Abstract: An adaptive data transfer channel providing means for a data management access method (AM) to define the channel subsystem data block transfer size and to transfer an extended data block (EDB) by a single channel transfer command to avoid repeated channel command word (CCW) command decode and status presentation operations. The adaptive scheme of this invention is transparent to the user and downwardly compatible with existing data record storage formats because it is independent of the user application program. The host software in the central processing complex (CPC) tests the peripheral data storage device (PDSD) to ensure compatibility with the EDB CCWs before selecting the channel program (CP) to be used for data block transfer in the subchannel. In the EDB format, the PDSD microcode permits the accumulation of logical data blocks (LDBs) from storage to form a single large EDB before transfer to the CPC responsive to a single transfer command.

Abstract: An adaptive data transfer channel providing means for a data management access method (AM) to define the channel subsystem data block transfer size and to transfer an extended data block (EDB) by a single channel transfer command to avoid repeated channel command word (CCW) command decode and status presentation operations. The adaptive scheme of this invention is transparent to the user and downwardly compatible with existing data record storage formats because it is independent of the user application program. The host software in the central processing complex (CPC) tests the peripheral data storage device (PDSD) to ensure compatibility with the EDB CCWs before selecting the channel program (CP) to be used for data block transfer in the subchannel. In the EDB format, the PDSD microcode permits the accumulation of logical data blocks (LDBs) from storage to form a single large EDB before transfer to the CPC responsive to a single transfer command.

Abstract: A method for managing data in a data storage hierarchy, and a data storage hierarchy suitable therefor, is disclosed. The data storage hierarchy includes an optical library and separate manually operated shelf storage. The optical library includes at least one optical disk drive and a plurality of storage cells for the storage of optical disks. The optical library also includes automatic means for transferring optical disks from the storage cells to the optical disk drives in the library. The host processor, upon determining that particular data is required to be stored in the optical library, first checks to determine if the optical disks in the optical library currently have the capacity for the storage of such data. If the capacity exists in the optical library there is no problem and the data is stored therein.

Abstract: A peripheral data storage hierarchy includes three storage levels. The top storage level is a fast accessing direct access storage device(s), such as magnetic disk drives. The intermediate level is an automatic warehouse type library, storing a large plurality of optical disks, which are automatically transferred between storage cells of the library and optical disk drives operatively connected to the host processor. The bottom level of the storage hierarchy includes one or more stand-alone optical disk drives and a shelf unit. Personnel manually carry the optical disks between the stand-alone drives and the shelf unit upon mount and demount commands received from the host processor. The intermediate library level uses the same type of optical disk as used in the bottom level of the data storage hierarchy. An I/O station in each of the automatic libraries enables manual access to the optical disk for transferring the optical disks between the intermediate and bottom levels.

Abstract: Image data objects are accumulated in a relatively rapid access data buffer, such as a combination of main memory and a rapid access magnetic DASD. An optical disk recorder having a record medium with a plurality of addressable sectors each capable of storing a predetermined number of the VTOC entries receives the accumulated data objects along with the associated VTOC entries in a single access whenever the number of accumulated data objects is an inegral number of said predetermined number. A lower threshold for a minimal number of data bytes of the accumulated data objects may be required before such single access data recording operation is effected. An upper threshold of number of data bytes in the accumulated objects is also provided for causing the single access data transfer irrespective of the number of objects being an integral number of said predetermined number. The invention is advantageously practiced with a write-once, read-many record medium.