Re: Help Needed: Tape Backup Save Set

From: AEF (spamsink2001_at_yahoo.com)
Date: 08/12/05 

Date: 11 Aug 2005 15:53:55 -0700

Wayne Sewell wrote:
> >From: "AEF" <spamsink2001@yahoo.com>
> >X-Newsgroups: comp.os.vms
> >Subject: Re: Help Needed: Tape Backup Save Set
> >Date: 11 Aug 2005 11:33:01 -0700
>
> >
> >Wayne Sewell wrote:
> >> >From: "AEF" <spamsink2001@yahoo.com>
> >> >X-Newsgroups: comp.os.vms
> >> >Subject: Re: Help Needed: Tape Backup Save Set
> >> >Date: 10 Aug 2005 19:52:55 -0700
> >> >Organization: http://groups.google.com
> >> >Lines: 27
> >>
> >> >
> >> >Z wrote:
> >> >> William Webb wrote:
> >> >> > If you
> >> >> > MOUNT/FOREIGN tape_device tape_label
> >> >> > You can
> >> >> > BACKUP/LIST tape_device:*
> >> >>
> >> >> If you're going to use BACKUP, let VMS mount the tape for you.
> >> >
> >> >Uh, on a v5.4-1 system I had trouble using BACKUP to mount a tape. If I
> >> >put in a tape that was not the first save set volume it would screw up
> >> >with funny characters reported as the label. Using an explicit
> >> >MOUNT/FOR made everything work fine. Ever since then I tend to do an
> >> >explicit MOUNT first, except with standalone backup, of course!
> >> >
> >>
> >> This appears to be historical residue from the previous millenium. I was not
> >> able to reproduce this behavior on 7.3-2.
> >> [...]
> >>
> >
> >I currently don't have the problem, but 2 jobs ago I worked on a
> >VMScluster that had to 8mm Exabyte tape drives (I believe the brand
> >name was Cybernetics) and whenever I used BACKUP to MOUNT a second
> >volume of a save set it would not work at all. After recovering via ^Y
> >I would SHOW DEV the drive and it reported garbage characters for the
> >label name. It would not work at all unless I MOUNTed it serpartely.
> >Then I would get the warning message about it not being the first
> >volume of a save set and it would run fine.
>
> I have never used 8MM drives, but stuff like this is mild compared to the
> stories I have heard about them. Perhaps those unfortunate enough to be stuck
> with them must use a manual mount, but the rest of us can let backup do it.

I don't know how common my problem was elsewhere. At my current job I
have 4mm DAT TLZ07's and TLZ09's and they are often troublesome.
Reading a tape on a different drive sometimes gives parity errors part
way through the tape! If it's an alignment problem, why doesn't it crap
out right away?

> >I only mention this as an example where it was better to issue a
> >separate MOUNT command. I don't know what David's problem with this
> >was.
> >
> >Another example:
> >
> >If you want a certain default load-unload action, then you need to
> >issue a separate MOUNT command.
>
>
> By default load-unload, I assume you mean when using /release_tape. By default
> backup does not dismount/unload the tape at all, because you could issue
> another backup command to append another saveset.

Nope. Nothing to do with release_tape. I meant changing the default
behaviour of a dismount.

> >IOW, you can do MOUNT/NOUNLOAD, but you
> >can't do BACKUP/NOUNLOAD.
> >
>
> However, you can do dismount/nounload after the backup. You do *not* have to
> issue an explicit mount for this unless you use /release.
>
> backup
> dismount/nounload
>
> I do this all the time, and tapesys can be told to do it as well. On my
> tapesys test systems, I have DISMOUNT_QUALS set to "/NOUNLOAD", so that I don't
> have to go upstairs to reload tapes every time I run a test.
>
> Is
>
> mount/nounload
> backup/releas
>
> that much easier than
>
> backup
> dismount/nounload

When you have a batch job like the following:

$ SET VERIFY
$ MOUNT/FOR MKA0 /NOUNLOAD
$ BACK/LIST MKA0: ! or some other more interesting BACKUP
command !
$ EXIT

and you want the tape not to unload no matter what, YES!

Suppose I'm running the above command procedure in batch, then I go
home. From home I see it's messing up. I DELETE/ENTRY it and the tape
doesn't unload. No time to do a DISMOUNT/UNLOAD. Now, even though there
is no one at work, I can try it again.

Yeah, there are other ways to handle it. But so what? The other ways
are more typing.

[...]

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