Disks and tapes

Contents

• MSCP and TMSCP Controllers
• SCSI Controllers
• DSSI Subsystem
• CI Subsystem

Note on virtual tapes

The container file associated with a virtual tape drive can be compared to the tape cartridge used in a physical tape drive. Both store the data written to the tape device by the guest OS.

The size of virtual tape container files is limited only by space available in the emulator host file system.

Prerequisite to the examples below: a virtual tape device has been configured in the CHARON configuration file and it is not in use by the guest OS.

To perform backup:

1. The tape device may be issued the "unload" command and the container-file moved/deleted to insure proper status 
2. Initialize the tape device using standard guest OS procedure.
3. Perform backup.
4. Issue "unload" command to the tape device in the guest OS.
5. On the emulator host, move the *.vtape container file containing backup data for storage or further backup.

To restore from a backup:

1. The tape device may be issued the "unload" command to insure proper status.
2. On the emulator host, move or copy a *.vtape container file containing backup data onto the filename specified in the CHARON configuration file.
3. Perform restore.
4. Issue the "unload" command to the tape device in the guest OS.
5. Delete or move the container file in preparation for the next vtape operation.
   
   

CHARON does not support muti-volume backup for tape images. If some mutli-volume set (in form of tape images) has to be restored it is recommended to configure several tape drives in CHARON VM configuration file, assign each tape image to each tape drive and use them in the following way (OpenVMS example):