Operating System - OpenVMS
1748136 Members
3521 Online
108758 Solutions
New Discussion юеВ

Re: How to copy a save set on magnetic tape to a disk?

 
P Muralidhar Kini
Honored Contributor

Re: How to copy a save set on magnetic tape to a disk?

Hi Jon,

>> ------------------
>> $ MOUNT/FOR
Let There Be Rock - AC/DC
Shriniketan Bhagwat
Trusted Contributor

Re: How to copy a save set on magnetic tape to a disk?

Hi,

Please let us know is there any specific requirement to copy the saveset from tape to disk?

Regards,
Ketan
Hoff
Honored Contributor

Re: How to copy a save set on magnetic tape to a disk?

Tape Tips: Magnetic Tape File Access, Copy

http://labs.hoffmanlabs.com/node/810

Includes the details of why the copies can have issues, of how, and links to Freeware tools, and how to copy files using COPY in its block-mode operation.

The issue around tape errors is of processing media errors received from the tape drivers.

BACKUP can detect and try to recover from an error, and BACKUP (defaults) to embedding error recovery data, and will seek to try to use that recovery data to rebuild the saveset. For minor errors, BACKUP can recover lost blocks.

When COPY receives a media error, it exits.

The case could be made that tape-level (firmware) ECC (which has vastly improved) might be enough for your needs.

And an open question is whether an error reported by the firmware within a modern tape drive is even recoverable; if the drive firmware will even accept the attempt to work through the error as implemented by BACKUP.

But even with tape-level ECC recovery and the pleasant fiction of error-free correct media that can be presented by disks and likely many tapes, COPY will encounter RMS limits on some tapes; with media recorded with larger block factors.