Operating System - OpenVMS
cancel
Showing results for 
Search instead for 
Did you mean: 

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

 
Mulder_1
Frequent Advisor

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

Can anyone please let me know how to copy a save set on magnetic tape to a disk ?

thanks
22 REPLIES 22
P Muralidhar Kini
Honored Contributor

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

Hi,

To copy a saveset in tape to disk
1) You need to first load the Volume that has the saveset on to the drive

2) Mount the tape device
MOUNT/FOR
Let There Be Rock - AC/DC
Volker Halle
Honored Contributor

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

FOX2,

please try to use more meaningful subjects ion the future...

$ BACK/LIS tape:/SAVE

Note Save Set name: xxx.bck
Note Block size: nnnn

CTRL-Y

$ DISM/NOUNL tape:
$ MOUNT/OVER=ID/NOWRITE/BLOCK=nnnn tape:
$ COPY/LOG tape:xxx.bck <>
$ DISM/NOUNL tape:

Verify copied saveset with:

$ BACKUP/LIST xxx.bck/SAVE

Volker.
P Muralidhar Kini
Honored Contributor

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

Volker,

>> /BLOCK=nnnn
Is this to ensure that the block size is chosen based on what it is for the
saveset (i.e. based on how the saveset was written). Otherwise when
accessing the saveset, the block size would be taken as default of 2048 byte
blocks (for tape).

Regards,
Murali
Let There Be Rock - AC/DC
Volker Halle
Honored Contributor

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

Murali,

your commands restore the CONTENTS of the saveset to disk. My commands copy the SAVESET itself to disk.

Regarding MOUNT/BLOCK please see HELP MOUNT/BLOCKSIZE.

Volker.
P Muralidhar Kini
Honored Contributor

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


>> your commands restore the CONTENTS of the saveset to disk.
>> My commands copy the SAVESET itself to disk.
Yes thats right.
Typo in my reply. The commands were to restore the contents of saveset.

In any case, thats good for FOX2.
He has also got the set of commands to restore a tape saveset to disk.
You can use that whenever the need arises.

Regards,
Murali
Let There Be Rock - AC/DC
Mulder_1
Frequent Advisor

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

Thanks

Just want to copy the save set as it is
Shriniketan Bhagwat
Trusted Contributor

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

Hi,

BACKUP saveset mentains tranportablility. i.e. saveset created on tape can be copied to disk and disk to tape.

>> Just want to copy the save set as it is

Just curious to know why you want to copy the saveset from tape to disk? is there any specific resion?

Regards,
Ketan
Volker Halle
Honored Contributor

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

FOX2,

please note that there is at least ONE restriction: if the backup saveset block size is greater than 32767, you can't copy it from tape, as this execeeds the maximum RMS block size supported for tape operations.

See the discussion in the following thread:

http://forums13.itrc.hp.com/service/forums/questionanswer.do?&threadId=1007124

Volker.
Shriniketan Bhagwat
Trusted Contributor

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

Hi,

BACKUP uses by default 8192 blocks while writing to the magnetic tape until and unless /BLOCK_SIZE qualifier with some
block size value is specified in the BACKUP command. You can determine this by listing the saveset on tape.
BACKUP/LIST xxx.bck/SAVE. Check the BLOCK SIZE field in the saveset summery which is listed in the beginning of the saveset.

>> please note that there is at least ONE restriction:

This is because BACKUP uses RMS $PUT while writing to disk and $QIO while writing to tape. Maximum block size that can be written through $PUT is 32767. Hence if the saveset was written to tape with block size more than 32767 can not be copied to disk. This restriction will not be applicable to those savesets on tape which were written with less than 32767 block size.

Regards,
Ketan

Andy Bustamante
Honored Contributor

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

As discussed by Volker and Shriniketan, the supported BLOCK size on tape is larger than on disk.

There is a layered product, SAVE SET MANAGER which will copy backup save sets and allow adjusting the block factor. Save Set Manager requires additional licensing.

If you don't have time to do it right, when will you have time to do it over? Reach me at first_name + "." + last_name at sysmanager net
John Gillings
Honored Contributor

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

Also note...

I recall that (for reasons opaque to mere mortals) copying savesets directly from magnetic tape using COPY is NOT supported.

I've never heard of it actually failing, but apparently the possibility exists, even apart from the block limits. YMMV, but don't complain if it doesn't work.

The supported mechanisms are BACKUP and SAVE SET MANAGER.
A crucible of informative mistakes
John McL
Trusted Contributor

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

Further to JG's comment, from the start of chapter about Backup in the Sys Mgr Utils Manual Part 1 ..."(A save set stored on a Filesâ 11 disk is a standard OpenVMS file, however, and can be copied, renamed, deleted, or backed up. A save set stored on magnetic tape should only be processed with the BACKUP command; do not use the DCL command COPY to copy a magnetic tape save set to disk.)"

Also ... "By default, BACKUP treats an input or output specifier referring to a Filesâ 11 disk as a file specification. Therefore, to identify a save set on a Filesâ 11 volume, you must include the /SAVE_SET qualifier with the specifier (see /SAVE_SET). BACKUP treats input and output specifiers referring to magnetic tape as save sets."

In case you are tempted to try $ BACKUP :XXX.SAV :XXX.SAV/SAVE (i.e. using Backup to copy the saveset onto the disk) the documentation says ..."You cannot specify a save set for both the input and output specifier of a BACKUP command. For this reason, you cannot perform a BACKUP operation from one magnetic tape to another."
Steven Schweda
Honored Contributor

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

> I recall that [...]

My dim (possibly defective) recollection is
that this had something to do with BACKUP's
sophisticated error handling, which might
cause it to rewrite some blocks to a tape in
ways which would confuse COPY.

> I've never heard of it actually failing,
> [...]

Nor I, but I haven't done it in recent years.
Can't recall having seen a tape write error
in a long time, either.

The biggest problem I ever had was doing any
tape copying as user SYSTEM, whose default
directory involves a search-list logical
name, causing everything to get done twice.
(Pain in the butt with a TK50. (As I said,
it's been a while.))
P Muralidhar Kini
Honored Contributor

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

Hi John,

You are right. The OpenVMS System manager's Utilities manual does say that
the saveset present on tape should be copied to disk using the BACKUP
command and not the COPY command.

Its a long time since I have played around with the savesets on tape.
I did not have to copy savesets from tape to disk many times but on occassions
when I had to, I remember getting in trouble when I did a MOUNT/OVER=ID of
the tape followed by a DIR and COPY command. I used to think that the
problem might be with the tape. But then when i do a MOUNT/FOR and use the
BACKUP command it used to work. The BACKUP command would
successfully copy the saveset from tape to disk.

>> $ BACKUP :XXX.SAV :XXX.SAV/SAVE
May be this command needs a slight change.
Since we only have to copy the saveset from the tape to disk, i dont think the
/SAVE qualifier is required at the destination. In general, for the BACKUP,
if it should perform a copy operation then the "/SAVE" is not required in the
source or destination.

So the command for FOX2 would be -
$ 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,

I did a small test and below are the results.
I created a saveset on tape and copied it to disk through BACKUP. When I tried to list the saveset on disk, it gave me the error %BACKUP-F-NOTSAVESET. I tried to repair the saveset but of no use. Then I used DCL copy command to copy the saveset from tape to disk and its working. Please refer the attached log for more details.

Regards,
Ketan
Jon Pinkley
Honored Contributor

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

Ketan,

Your test wasn't doing what you thought it did; it didn't copy the saveset to disk.

From your test:
-------------------------
$ backup/log PHYSICAL.LIS;2 $2$MGA5:test.bck/save/ignore=label
%BACKUP-S-COPIED, copied SYS$SYSDEVICE:[BACKUP]PHYSICAL.LIS;2
$
$ backup/log/rewind/ignore=label $2$MGA5:test.bck []test.bck
%BACKUP-S-CREATED, created SYS$SYSDEVICE:[BACKUP]TEST.BCK;2
$ dir test.bck

Directory SYS$SYSDEVICE:[BACKUP]

TEST.BCK;2

Total of 1 file.
$ backup/list SYS$SYSDEVICE:[BACKUP]TEST.BCK;2/save
Listing of save set(s)

%BACKUP-F-NOTSAVESET, SYS$SYSDEVICE:[BACKUP]TEST.BCK;2 is not a BACKUP save set
-------------------------


The command: $ backup/log/rewind/ignore=label $2$MGA5:test.bck []test.bck

is restoring PHYICAL.LIS;2 from the test.bck saveset to a specified file name []TEST.BCK

The version ;2 is coming from rms parsing from PHYICAL.LIS;2

$ set def sys$sysdevice:[backup]
$ write sys$output f$parse("TEST.BCK","[]PHYSICAL.LIS;2")
SYS$SYSDEVICE:[BACKUP]TEST.BCK;2
$

If you would have issued the command:

$ differences physical.lis;2 test.bck;2

you would have gotten


Number of difference sections found: 0
Number of difference records found: 0

DIFFERENCES /IGNORE=()/MERGED=1-
SYS$SYSDEVICE:[BACKUP]PHYSICAL.LIS;2-
SYS$SYSDEVICE:[BACKUP]TEST.BCK;2
$

If the save set would have had more than a single file in it, what was happening would have been more obvious.

Backup is powerful, but it isn't always obvious what a command is doing.

Jon
it depends
Shriniketan Bhagwat
Trusted Contributor

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

Hi,

Yes Jon, you are correct.

Regards,
Ketan
Volker Halle
Honored Contributor

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

As far as I recall, continuation tape handling, which could be different between BACKUP and COPY, could also be a problem and may be a reason, why COPYing savesets from tape is not supported.

Volker.
Jon Pinkley
Honored Contributor

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

FOX2,

As Ketan demonstrated, the commands that were given by Murali,
------------------
$ MOUNT/FOR
it depends
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.