BSAM, BPAM interface

Offset Bytes in Length Field Name Description
61(3D) 1 DCBCIND2 Condition indicators.
    .... .1.. DCBCNCHS. Chain scheduling being supported. Set in OPEN. Zero for DASD. May differ from OPTCD=C bit(DCBOPTC).
72(48) 1 DCBNCP Number of channel programs. Number of READ or WRITE requests that can be issued before a CHECK. Maximum number: 255.
80(50) 1 DCBUSASI/ DCBLBP ASCII tape. Block prefix.
    .1.. .... Block prefix is a 4-byte field containing the block length.
81(51) 1 DCBBUFOF Block prefix length.
82(52) 2 DCBLRECL Logical record length. For fixed-length blocked record format, the presence of DCBLRECL allows BSAM to read truncated records. For undefined records, this field contains block size.