dwu@nunki.usc.edu (Daniel Wu) (07/15/89)
OOPS! OOPS OOPS! OOPS! I was trying to load a file from the cartridge tape recently, by typing tar -xvf /def/rst0 ./doc/README However, what I ACTUALLY typed was: tar -cvf /def/rst0 ./doc/README That immediately corrupted my cartridge tape. Instead of extracting the file README from the tape, it tried to copy a non-existent file ./doc/README from by directory onto the tape. Now what do I do? Am I completely out of luck, or is there some way to reconstruct whatever files were on tape? If anyone can offer help or suggestions, I'd really appreciate it. I need help FAST!! Daniel dwu@castor.usc.edu ================================================================= Daniel Wu ARPA: dwu@castor.usc.edu UUCP: ? dwu@castor.UUCP ? I'm not very familiar with the backbone sites this
chris@mimsy.UUCP (Chris Torek) (07/15/89)
In article <4385@merlin.usc.edu> dwu@nunki.usc.edu (Daniel Wu) writes: >... from the cartridge tape .... This question goes 'round and 'round. Where it will stop, nobody knows. Anyway, here are the facts as stated, distilled to their essence: `tar file', `cartridge tape', `overwritten with c option but naming a nonexistent file'. There are only about 30 gazillion different cartridge formats, so I suppose we have to guess which one was used. Many QIC (Quarter Inch Cartridge) tape devices and/or standards do not allow reading past what the hardware thinks is the end of the tape. If this is the case, you are out of luck. If you can find some way physically to read the data, there is a program called `fixtar' floating around the net, and various other similar programs (likewise lighter-than-net), which you can use to recover most of your data. If you study tar(5) in TFM you may be able to recover even more data. If you are truly desperate, you can remove the tape from its holder, develop it chemically, and read the magnetic domains with a microscope. In some cases this will allow you to read data that has been overwritten (that is, read the `second layer down'). -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris
pvo@uther.CS.ORST.EDU (Paul V O'Neill) (07/16/89)
In article <18567@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes: > > [lots of good stuff], ..... especially ... > >...similar programs (likewise lighter-than-net), which you can use to >recover most of your data...... Keep in mind that if you made the c/x error while at BOT, or anywhere on track 1 of a QIC tape, that the drive turned on it's FULL WIDTH erase head as it was writing to track 1 and also wiped anything you had further on down the line in tracks 2 - 9. :-| Have a day. Paul O'Neill pvo@oce.orst.edu Coastal Imaging Lab OSU--Oceanography Corvallis, OR 97331 503-737-3251
cdl@mplvax.EDU (Carl Lowenstein) (07/17/89)
In article <11668@orstcs.CS.ORST.EDU> pvo@oce.orst.edu (Paul V O'Neill) writes: >Keep in mind that if you made the c/x error while at BOT, or anywhere on >track 1 of a QIC tape, that the drive turned on it's FULL WIDTH erase head >as it was writing to track 1 and also wiped anything you had further on >down the line in tracks 2 - 9. Do these QIC cartridges not have some kind of mechanical write lock that signals to the drive electronics? One could save a great deal of grief by exercising the write lock, assuming that it really works. Maybe that's the only good feature of the DEC TK50 cartridge, the write-lock mechanism out front where it can be switched over. Much easier than the write-enable ring on a standard 9-track tape. -- carl lowenstein marine physical lab u.c. san diego {decvax|ucbvax} !ucsd!mplvax!cdl cdl@mpl.ucsd.edu
rg@psgdc (Dick Gill) (07/18/89)
In article <970@mplvax.EDU> cdl@mplvax.ucsd.edu.UUCP (Carl Lowenstein) writes: >In article <11668@orstcs.CS.ORST.EDU> pvo@oce.orst.edu (Paul V O'Neill) writes: > >>Keep in mind that if you made the c/x error while at BOT, or anywhere on >>track 1 of a QIC tape, that the drive turned on it's FULL WIDTH erase head >>as it was writing to track 1 and also wiped anything you had further on >>down the line in tracks 2 - 9. > >Do these QIC cartridges not have some kind of mechanical write lock that >signals to the drive electronics? ... They sure do, at least the 3M-DCxxx series cartridges used on NCR Towers, IBM RT's, Fortunes and, I suspect, many other unix machines. Looking at the upper left corner of the cartridge (with the tape at the top) you will see a circular plastic piece with a slot in it and an arrow on it. To the right will be the word 'safe'. If you turn the circular plastic piece so that the arrow points to the word 'safe', tape drives will not be able to write on the cartridge. When we have clients who REALLY need the data on a backup tape (disc crash, major upgrade, etc.), the first thing we instruct them to do is to turn the arrow to SAFE on the backup casettes. It takes no time, and offers protection against the unfortunate slip of the finger which can wipe out your safety net in a second. -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dick Gill Professional Solutions Group (703)761-1163 ..uunet!psgdc!rg
cudcv@warwick.ac.uk (Rob McMahon) (07/19/89)
In article <970@mplvax.EDU> cdl@mplvax.ucsd.edu.UUCP (Carl Lowenstein) writes: >Maybe that's the only good feature of the DEC TK50 cartridge, the write-lock >mechanism out front where it can be switched over. Much easier than the >write-enable ring on a standard 9-track tape. Ugh, you mean the write lock is on the drive rather than the tape ? Surely readonliness is a function of the tape, not the drive. How much easier is it to accidentally forget to switch the write-lock on than to accidentally put in a write-ring ... does this mean DEC TK50s have *no* good features ? Rob -- UUCP: ...!mcvax!ukc!warwick!cudcv PHONE: +44 203 523037 JANET: cudcv@uk.ac.warwick ARPA: cudcv@warwick.ac.uk Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England
cdl@mplvax.EDU (Carl Lowenstein) (07/19/89)
In article <172@titania.warwick.ac.uk> cudcv@warwick.ac.uk (Rob McMahon) writes: >In article <970@mplvax.EDU> cdl@mplvax.ucsd.edu.UUCP (Carl Lowenstein) writes: >>Maybe that's the only good feature of the DEC TK50 cartridge, the write-lock >>mechanism out front where it can be switched over. > >Ugh, you mean the write lock is on the drive rather than the tape ? Surely >readonliness is a function of the tape, not the drive. >... does this mean DEC TK50s have *no* good features ? You misconstrue me. The write lock is on the tape cartridge, but it is on the outer face, so it can be changed while the cartridge is still in the drive. -- carl lowenstein marine physical lab u.c. san diego {decvax|ucbvax} !ucsd!mplvax!cdl cdl@mpl.ucsd.edu