There are some special coding considerations for VSAM files under z/OS and UNIX for access method services (IDCAMS) commands, environment variables, and JCL.
A VSAM file is available if all of the following conditions are true:
A VSAM file is unavailable if it has never contained a record, even if you have defined it.
You always get a return code of zero on completion of the OPEN statement for a VSAM sequential file.
Use the access method services REPRO command to empty a file. Deleting records in this manner resets the high-use relative byte address (RBA) of the file to zero. The file is effectively empty and appears to COBOL as if it never contained a record.