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Conference stkhlm::magtape

Title:MAGNETIC TAPEDRIVES
Moderator:STKHLM::GJOHNSSON
Created:Mon Sep 21 1987
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3775
Total number of notes:13147

3723.0. "INIT not deleting old data (TZ88 w/ Compact IV) ?" by FOUNDR::DODIER (Double Income, Clan'o Kids) Tue Apr 15 1997 16:56

    	I have a TL812 (TZ88s) that appears not to be deleting previous
    save set information when the tape is reinitialized. Two things that
    have happened are -
    
    	1. Put four stripe-sets (4 RZ29s each) worth of image backup save 
    	   sets to a tape. Re-initialized the tape and reattempted exact same
    	   backup and less than two stripe-sets would fit on the same tape.
    
    	2. Initialized a tape that had previous save sets on it and did a 
    	   backup of one stripe-set to this tape. When I tried to restore
    	   the save set back to a freshly initialized stripe-set, it failed 
    	   after a long time saying that the disk (stripe-set) was full.
    
    	In each case, the command used to initialize the tape was -
    
    	$ INIT/COMPACT MKxxxxx CPG95
    
    	I am adding a /ERASE to the above INIT command and will reattempt
    the process. Is this a feature or a bug ? I don't suppose many people
    attempt to do what I've done, so I suspect that this is not a common
    problem. 
    
    	This is on an 8400 running VMS V7.1 with the TL812 connected via
    4 seperate KZPSAs.
    
    	Ray
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3723.1GEM::SHERGOLDWe are 100% sure; well almost!!Wed Apr 16 1997 13:059
     
    
    $ INIT/MEDIA=COMP MKxxx
    	   ==========
    
    and the tape drive COMPRESS light should light. If it doesn't
    investigate why.
    
    Keith
3723.2Undocumented featureFOUNDR::DODIERDouble Income, Clan'o KidsWed Apr 16 1997 16:1928
    	Well, I guess that's a feature ;-) OpenVMS V7.1 will accept the 
    command INIT/COMPRESS without complaining about syntax. Being that most
    of the operations are on a TL812, opening the door to look at the drives 
    takes the tape drives off-line.
    
    	I also tried just a vanilla flavored INIT without compression and
    it still fails the same way. I should note that this has worked, sometimes. 
    Yes, I have gotten it to work a couple of times, but there's no rhyme or 
    reason to it. It worked once on a TZ88 connected to an HSJ40 via a BA350 
    box, and it worked once on one of the TL812 drives, both on the same system.
    
    	The exact error is -
    
    %BACKUP-F-CLOSEOUT, error closing DEPOT8$MKQ500:<>DISK7I.SAV;1 as output
    -SYSTEM-W-BLOCKCNTERR, block count error
    
    	I went back and looked at the BACKUP info in the System Management
    Utilities Reference manual and it says that BACKUP will mount the tape
    drives itself. I've been mounting them manually with a MOUNT/FORIEGN
    command. I'll retry it letting BACKUP do the mount and see if it makes
    any difference.
    
    	Ray
    
    BTW - Out of curiousity, I did an INIT/COMPRESS on the TZ88 connected
    to the HSJ40 (because I can easily see that one) and it did in fact light 
    the compress light. An operating system that knows what I meant. Ya gotta 
    love it ;-)
3723.3Part way thereFOUNDR::DODIERDouble Income, Clan&#039;o KidsWed Apr 16 1997 21:148
    	Apparently, it makes a difference if BACKUP mounts the tape. It
    seems to work fine when you let it do that. I'm still left wondering 
    about why I could not get two save sets to fit on a tape where 4 1/2 
    save sets (multi-volume) previously did, and why the disk fills when 
    trying to restore a tape with a single save set on it to a stripe-set 
    that it should easily fit on.
    
    	Ray
3723.4DECWET::RWALKERRoger Walker - Media ChangersSat Apr 19 1997 01:067
	You should be able to open the door of the TL81x while the
	drives are in use.  It will reset the robotics but the drives
	should continue to run.  This is how I check the density/compression
	settings (or even override them for a test).

	Just don't change tapes until the door is closed and the 
	inventory is over.
3723.5COOKIE::FROEHLINVMS...riding into the setting sun!Sat Apr 26 1997 02:0732
.2> 	Well, I guess that's a feature ;-) OpenVMS V7.1 will accept the 
.2> command INIT/COMPRESS without complaining about syntax. Being that most
    
    The INIT code takes the same action on /COMPACTION and
    /MEDIA=COMPACTION. The /COMPACTION qualfier is undocumented, though.
    Also DCL only looks at the 1st 4 characters of a qualifier.
    
.2> %BACKUP-F-CLOSEOUT, error closing DEPOT8$MKQ500:<>DISK7I.SAV;1 as output
.2> -SYSTEM-W-BLOCKCNTERR, block count error
    
    Hm, this is kind of strange. Only the magtape ACP returns this block
    count error. And BACKUP is not using the magtape ACP. I've never seen a
    MKQnnn device. What kind of HW controller and tape driver is being used 
    here?
    
.3>    	Apparently, it makes a difference if BACKUP mounts the tape. It
    
    Only if /REWIND is being used. BACKUP only changes the
    density/compaction if at BOT and /REWIND is specified.
    
.3> about why I could not get two save sets to fit on a tape where 4 1/2 
.3> save sets (multi-volume) previously did, and why the disk fills when 
.3> trying to restore a tape with a single save set on it to a stripe-set 
.3> that it should easily fit on.
    
    Hm, sounds like the save operation was not a true /IMAGE and some
    directory trees have been saved multiple times. Was this a system disk?
    Would also explain why the restore failed. Could you show the summary
    header of a BACKUP/LIST which contains the BACKUP command line being
    used?
    
    Guenther