Conference noted::hackers_v1

99.0. "'filter' fools BACKUP" by TRUTH::FALEK () Fri Mar 08 1985 11:23

If you try to BACKUP to a tape drive on a remote node using

$ BACKUP FILESPEC REMOTE::MFA0:A.BCK/SAV

then (assuming you've put a tape on the drive and got it to mount somehow)
the tape moves, something gets written, and BACKUP reports success.
BUT... if you try to do a restore or a BACKUP/LIST, then BACKUP complains
that a.bck is not a backup saveset. The problem is the records written
have the varying length attribute, even though the right data is there
and the records all happen to be the same length.

Using CONVERT as a filter for sys$net results in a saveset that BACKUP
considers valid:

$ BACKUP/BLOCK=4096 FILESPEC REMOTE::"TASK=REMBCK"/SAV
	where REMBCK.COM on the remote node is:

$ INIT MFA0: LABEL
$ MOUNT/BLOCK=4096 MFA0: LABEL
$ ON ERROR GOTO DISMOU
$ CONVERT/FDL=SYS$INPUT: SYS$NET: MFA0:A.BCK
RECORD
	FORMAT			FIXED
	SIZE			4096
$ DISMOU:
$ DISMOUNT MFA0:
$ EXIT

This works correctly, even for multi-volume savesets. (when a tape gets full
it gets dismounted and an opcom message asking for another gets generated,
you say REPLY/TO=nnnn to tell opcom that the new tape is up, like normal).

Can anyone think of a way to put the filter on the OTHER side of the network
link so that the tape can be restored to the originating node without first
restoring to disk on the machine with the tapedrive?

By the way, this is a generally useful technique, for example you could copy
a file to another node, changing all occurances of string "A" to string "B"
in the process.     -Lou F.

Gulp... so who says VMS doesn't have Pipes?  I think you just blew away
the only reason for anyone to even consider Unix... :-)

	Paul

Re .-1
I think that's taking "THE NETWORK IS THE SYSTEM" too far, Paul!

Nigel