Example: Record format *VBS
Here is an example of record format *VBS.
Variable-length, blocked, spanned (*VBS).
XX and YY make up the BDW for each data block. XX is the length of all records in each block plus the length of the BDW (4 bytes). YY represents currently reserved fields and must be 00. XX should be the actual length of the data block that is written.
Note that logical record B spans across three actual data blocks on the tape.
- 00 binary - Complete logical record
- 01 binary - First segment of a multi-segment record
- 10 binary - Last segment of a multi-segment record
- 11 binary - Middle segment of a multi-segment record
The second byte of the control character is reserved, and should be 0. TT should be the actual length of record data segment plus the length of the SDW (4 bytes).
From a user's point of view, a logical view of record B is the the same as other records defined above.