Safe Tape Erasure – Function TAPERAS

The CTTTPI utility protects active volumes from being erased by comparing the specified volume serial number and the volser of the mounted volume, before erasing the data on the tape. Volumes are protected regardless of whether they appear in the Media database.

CTTTPI uses an operating system function (‘Data Security Erase’ EXCP) to erase tapes. This function writes a random pattern of data on the specified tape.

The erase function is generally invoked as a started task using the following command:

where

• volser is the volume serial number of the tape to be erased.
• unitname is the type of the unit in which the specified tape is loaded.
• devnum is the number of the device in which the specified tape is loaded.

This command invokes the utility with the following single control statement:

When invoked in this manner, the utility first checks that the specified target volume serial number is either not in the Media database or is in the Media database with scratch status.

If the target volume serial number passes the first check, the utility requests that the operator mount the physical volume. Once the volume is mounted, the utility reads it to verify that it is not an active volume in the Media database.

The mounted volume is erased only if the volser of the mounted volume matches the volser specified in the JCL for the utility.

If the specified volser is numeric, the utility requests successive volumes in ascending order until stopped or canceled by the operator.

The utility issues messages (for example, CTT289A) and sometimes prompts the operator for a reply or decision. If Control-O or Control-M/Links for Windows NT is installed at your site, responses to these messages can usually be automated.

Depending on specified parameters, the Media database can be updated by the utility.