You can define VSAM records to be fixed or variable in length. COBOL determines the record format from the RECORD clause and the record descriptions that are associated with the FD entry for a file.
Because the concept of blocking has no meaning for VSAM files, you can omit the BLOCK CONTAINS clause. The clause is syntax-checked, but it has no effect on how the program runs.
related tasks
Defining fixed-length records
Defining variable-length records
Enterprise COBOL Compiler and Runtime Migration Guide
related references
FILE SECTION entries