BS2000 supports volumes with different formats:
Key volumes for storing files in which the block control information is maintained in a separate field ("Pamkey") per 2 Kbyte data block. These files have the block format PAMKEY.
Non-Key volumes for files without separate Pamkey fields. The block control information is either omitted (block format NO) or stored in the respective data blocks (block format DATA).
Additionally, NK volumes are distinguished by the minimum size of the transfer unit. NK2 volumes have the old transfer unit (2 Kbytes). NK4 volumes have a transfer unit of 4 Kbytes.
The block format is controlled by the BLOCK-CONTROL-INFO operand in the ADD-FILE-LINK command.
Please refer to the "DMS Introductory Guide" manual for a detailed description of the BLOCK-CONTROL-INFO operand, various file and data volume structures and the conversion from K file format to NK file format.
Please refer to the "DMS Introductory Guide" manual [11] for a detailed description of the BLOCK-CONTROL-INFO operand, various file and data volume structures and the conversion from K file format to NK file format.
If the ADD-FILE-LINK command is not used when creating a new file or BLOCK-CONTROL-INFO=BY-PROGRAM is specified, the default values of the C runtime library are used. These values depend on the disk format, on the value of the system parameter BLKCNTRL, and on the access method:
File organization | system parameter | |||
not specified | specified | |||
K disk | NK disk | K disk | NK disk | |
SAM | PAMKEY | DATA | DATA | DATA |
ISAM | PAMKEY | DATA | DATA | DATA |
PAM | PAMKEY | NO | NO | NO |