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Conference noted::hackers_v1

Title:-={ H A C K E R S }=-
Notice:Write locked - see NOTED::HACKERS
Moderator:DIEHRD::MORRIS
Created:Thu Feb 20 1986
Last Modified:Mon Aug 03 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:680
Total number of notes:5456

630.0. "Hackup Backup anyone?" by LESLIE::LESLIE (Andy, CSSE DECnet/OSI Program, WG5.) Wed Dec 16 1987 03:50

T.RTitleUserPersonal
Name
DateLines
630.1PracticalityVROSRV::HEAFEYWed Dec 16 1987 12:358
	I know this is a "close the barn door after the cow got out" answer
	but, when the output volume is magtape, ALWAYS INITIALIZE the tape.
	I've had the same experiences under 4.5 and 4.6. I realize that this
	isn't a very "technical" solution but, it is practical. As an operator
	my primary concern is being able to restore a user's files if the need
	arises.

	Dave H.
630.2RDGENG::LESLIEAndy, CSSE DECnet/OSI Program, WG5.Wed Dec 16 1987 14:223
    
    I DID initialise the !@#$%^ tape!! As far as I can see BACKUP OVERWROTE
    THE LABEL.
630.3RDGENG::LESLIEAndy, CSSE DECnet/OSI Program, WG5.Thu Dec 17 1987 07:349
    
    Anyhow, I initialised the tape, MOUNTED it /BLOCK =8192 and when
    I tried to copy the file I got                   
    
    -RMS-E-CRE, ACP file create failed
    -SYSTEM-F-BADATTRIB, bad attribute control list
    %COPY-W-NOTCOPIED, DUA1:[TAPE]TAPE.A;1 not copied
    
    More ideas please!
630.4RDGENG::LESLIEAndy, CSSE DECnet/OSI Program, WG5.Thu Dec 17 1987 11:391
    Worked out why that happened - RMS only allows 2048 byte records.
630.5How I've done it beforeOVDVAX::LENNIGDave, SWS, @CYO CincinnatiThu Dec 17 1987 16:3425
    Andy, I assume you did your MOUnts /FOR (you didn't indicate so).
    Reason I bring it up, is that if you didn't, the MTAACP will gobble
    up the VOL and HDR records on the tape, and DUMP won't see them.
    (At least that's the way I recall things.)
    
    Regardless, I have hacked together tapes like this before, and have
    a program (written in Fortran, slow as hell) that in conjunction
    with certain DCL commands will allow you to recreate your tape.
    
    The basic procedure I would use is...
    Run program, which reads blocks off the tape and writes them to
    disk, against the 'bad' tape. You now have a image of the tape.
    Mount a scratch tape, init it, and backup an 'empty' disk, using
    the same volume and saveset names as the prior attempt. Rewind
    the tape (SET MAG/REW) space it forward to the beginning of the
    first data block (SET MAG/???) and then run the program to copy
    the image back onto the tape.
    
    If you need a copy of the program (I got it from Z, who got it from
    Y, who got it from X...) send mail. There's nothing particularly
    fancy or unique about the program, it just issues QIO's to read
    the tape and WRITEs to disk.
    
    Good luck,
    	Dave
630.6I've been thereMAY20::MINOWJe suis marxiste, tendance GrouchoThu Dec 17 1987 21:156
Andy, feel free to copy BOLT::DECUSC$LIBRARY:[MISC]READTAPE.C or
BOLT::USER:[MINOW.BIN]READTAPE.EXE.

READTAPE was written to read Unix TAR tapes onto disk.

Martin.
630.7Idle questionLESLIE::LESLIEAndy, CSSE DECnet/OSI Program, WG5.Fri Dec 18 1987 06:121
    Where is BACKUP format documented?
630.8LESLIE::LESLIEAndy, CSSE DECnet/OSI Program, WG5.Fri Dec 18 1987 08:5813
    interesting.
    
    JC, a friend in need if ever there was one, has rebuilt the tape.
    
    The two problems were
    
    1) Backup overwrote the label
    2) the 'saveset' was marked as having variable length records, which
       meant that it wasn't a saveset, according to backup.
    
    A little twiddling and all is well.
    
    Thankfully.
630.9Where, oh whereMDVAX3::COARMy hero? Vax Headroom, of course!Fri Dec 18 1987 12:5510
    Re .7:
    
>    Where is BACKUP format documented?
    
    In the 'fiche.  It used to be in an .MDL file, but it's probably
    SDL by now.  Somewhere, I have a more-or-less complete copy of the
    .MDL file (that I typed in by hand - oh groan!).  Let me know if
    you want it..
    
    #ken	:-)}
630.10TUBORG::GROSSMANExpectation invites disappointmentSun Dec 20 1987 19:018
     The best document for the backup saveset format was found in
    appendix B of the V3 Utilities Reference Manual. To get an online
    feel for it try BACKUP/LIST/ANALYZE. This breaks up the saveset
    field by field and displays them. 
    
                                            - Russ -