Claims
- 1. In a data processing system having a central processing complex (CPC) with a channel subsystem (CS) for connecting to one or more peripheral data storage devices (PDSDs) each having formatting means for storing logical data blocks (LDBs) in any predetermined record format, said CPC also having input/output (I/O) means for creating a channel program (CP) to transfer data between said CPC and any said PDSD, said CP containing one or more channel control words (CCWs) including at least one transfer command (TC), each said CCW having a logical block length field of k=log.sub.2 n bits, wherein k and n are non-zero positive integers and wherein each said LDB includes no more than (n-1) bytes, a data object comprising:
- a plurality of said LDBs stored in a memory of the data processing system; and
- an extended block header (EBH) stored in the memory, said EBH having a header length field for specifying to a TC the length of said EBH, having a data object length field for specifying to a TC the length of said data object, and having one or more block descriptor fields, each for specifying to a TC a length of a respective LDB of said plurality of LDBs.
- 2. The data object of claim 1, wherein an LDB of said plurality of LDBs contains data.
- 3. The data object of claim 1, wherein an LDB of said plurality of LDBs contains marks.
- 4. The data object of claim 1, wherein a block descriptor field of said one or more block descriptor fields is a null lock descriptor.
- 5. In a data processing system having a central processing complex (CPC) with a channel subsystem (CS) for connecting to one or more peripheral data storage devices (PDSDs) each having formatting means for storing logical data blocks (LDBs) in any predetermined record format, said CPC also having input/output (I/O) means for creating a channel program (CP) to transfer data between said CPC and any said PDSD, said CP containing one or more channel control words (CCWs) including at least one transfer command (TC), each said CCW having a logical block length field of k=log.sub.2 n bits, wherein k and n are non-zero positive integers and wherein each said LDB includes no more than (n-1) bytes, a data object comprising:
- a plurality of said LDBs stored in a buffer of said PDSD; and
- an extended block header (EBH) stored in the buffer, said EBH having a header length field for specifying to a TC the length of said EBH, having a data object length field for specifying to a TC the length of said data object, and having one or more block descriptor fields, each for specifying to a TC a length of a respective LDB of said plurality of LDBs.
- 6. The data object of claim 5, wherein an LDB of said plurality of LDBs contains data.
- 7. The data object of claim 5, wherein an LDB of said plurality of LDBs contains marks.
- 8. The data object of claim 5, wherein a block descriptor field of said one or more block descriptor fields is a null lock descriptor.
- 9. The data object of claim 5, wherein said block descriptor fields are ordered corresponding to an order in which said plurality of LDBs is stored on a storage medium of said PDSD.
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a division of application Ser. No. 07/998,971, filed Dec. 30, 1992, now patented U.S. Pat. No. 5,517,670.
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Divisions (1)
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Number |
Date |
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Parent |
998971 |
Dec 1992 |
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