kelvin@thed (Kelvin Hill) (06/18/91)
Some time ago, a somewhat irate user reported that he had been using tar
to backup or restore some files from/to a hard disk, and that as a result
had had his root directory partially wiped. At the time, I thought 'pilot
error'and put it to the back of my mind.
I have now to reconsider this situation after a similar nightmare hit me
yesterday. This serves as both a warning and a request for advice. Let me
tell the (nearly) whole story.
Yesterday, I got a bit twitchy about not having backed up the 2 * 40Mb
ST506 drives in my 440/1+Arm3 system. So, I pre-formatted 120 floppies
to take the backups onto. As I have a 15Mb MS-DOS partition on each disk
I wanted to use tar to perform the backup, instead of the other method of
file by file copy. This is because the file by file methods won't save the
DOS areas.
I used the version of tar that comes with the !Extract/!Submit software
from comp.binaries.acorn, so it's fairly up to date. I also loaded the
FS_VARS module that tar seemed to require at one time. As far as I know
it may still do so.
I copied tar to a 256kb ram disk and made it my current directory. I then
fired tar up with the following command line.
tar -cvBf 10 adfs::1.$.Backup4 adfs::4.$
(The B and 10 are to use 5120 byte blocking. I *think* it's B not b.)
The first 3 floppies were saved to correctly and all looked wonderfull, BUT
halfway through the 4th floppy, the system crashed. Not just tar, but the
whole system just fell over. The screen cleared and the hard disk light came
on solid.
I did a ctrl-(reset button) to bring it back up and this is where the panic
set in. The hard disk adfs::4 was now badly corrupted and giving errors.
I now had 4 randomly located 'broken directories'. Of these, 2 were at root
level and 2 were subdirectories. I also had at least one damaged data file.
I suspect that there may well be more data file damage but it takes a long
time to check out 40Mb of individual files.
To cut the story short, I have recovered most of the broken directories,
reformatted and rebuilt both hard drives and tested some of the data files
on the corrupted disk. There is still a lot of checking to do though.
Summary.
-------
Tar has now been implicated twice in the corruption of hard disks during
'normal' operation. While this may be co-incidence, should we be using
this product to distribute software in comp.binaries.acorn? I for one
dont trust it any more!
Thats the warning bit over with... now for the request for advice...
What do people consider to be the best method of backing up my two hard
disks, considering the problem of the 15Mb DOS partitions? A SCSI tape
would be nice, but then so would the money to buy it! I have at the moment
to probably stick to diskettes. Any suggestions would be appreciated.
Kelvin.
--
Kelvin J. Hill - BULL HN Information System Ltd, Hounslow, England, UK.
Internet - kelvin@thed.uk22.bull.com | UUCP - kelvin@cix.compulink.co.uk
"" kelvin@kelvin.uk22.bull.com | AMPRnet - kelvin@g1emm.ampr.orgfl@tools.uucp (Frank Lancaster) (06/19/91)
tar will remind you if called with no parameters to READ THE DOCUMENTATION FILE and THAT I WILL TAKE NO RESPONSIBILITY FOR ANY DATA LOSS DUE TO THE USE OF THIS PROGRAMME. I must say that I myself use tar on regular basis and I do not have any problems anymore. The bug that could delete some or all of your hard disc was removed ages ago. If you read the history section in the documentation you would have realised this. I released the tar programme into the public domain because I thought it a very useful utility. But as people who have some kind of trouble using it or with their hard disc always seem to see the fault in the programme I will now stop supporting it. I am fed up! Some people would probably write to AT&T and say that UNIX has a bug because if you rm -rf * it deletes all your files without saying anything. It was a bad idea that tar was released with submit/extract without the documentation, but I was preparing a release for comp.binaries.acorn with some changes suggested by several users. This will now not be done. You can buy a commercial backup programme and sue the company if it doesn't work, I have a heavy work load (some people do have to work for a living) and do not have the time to support a PD programme which is supposed to satifies everyone's idea of ease of use and safety. Frank Lancaster
arb@comp.lancs.ac.uk (Andrew Brooks) (06/19/91)
In article <kelvin.677235945@thed> kelvin@thed (Kelvin Hill) writes: > >Tar has now been implicated twice in the corruption of hard disks during >'normal' operation. While this may be co-incidence, should we be using >this product to distribute software in comp.binaries.acorn? I for one >dont trust it any more! Make that three times. A serious user here at Lancaster tried using Tar to back up his hard disc, and it worked OK for his applications, but completely trashed the directories containing his data files. How can a program that is only supposed to read from disc write over directories? >To cut the story short, I have recovered most of the broken directories, How do you recover broken directories? Andrew.
kers@hplb.hpl.hp.com (Chris Dollin) (06/19/91)
Frank Lancaster says: I released the tar programme into the public domain because I thought it a very useful utility. But as people who have some kind of trouble using it or with their hard disc always seem to see the fault in the programme I will now stop supporting it. I am fed up! I sympathise with you, Frank. But as a last gasp of support could you release the sources - then at least those of us prepared to program could continue to get the benefit. [I don't use tar for backup [yet]; I use it for moving stuff between my Arc and my HP machine at work, using !PCDir to do the actual file copying ...] -- Regards, "I know three kinds: hot, cool, and 'what time does the tune start?'". Kers [The Beiderbeck Connection]
jho@imada.ou.dk (Jens H. Ovesen) (06/19/91)
fl@tools.uucp (Frank Lancaster) writes: >I released the tar programme into the public domain because I thought it a very >useful utility. But as people who have some kind of trouble using it or with >their hard disc always seem to see the fault in the programme I will now >stop supporting it. I am fed up! Some people would probably write to AT&T and I too find it a very useful utility. People using it without reading the documentation are fools anyway. Never use PD which is made for some HD purpose without reading doc. I must say it's a pitty you'll stop supporting it. There is bugs in all programs, and people using the programs should be welcome to report such bugs, without the author being "fed up". On the other hand, such reports should be in a kind language, those I've seen have been so. >It was a bad idea that tar was released with >submit/extract without the documentation, Yes it was. >but I was preparing a release for >comp.binaries.acorn with some changes suggested by several users. This will >now not be done. Come on. Why not? Don't get so offended. *I* would like to see it. >(I) do not have the time to support a PD programme which >is supposed to satifies everyone's idea of ease of use and safety. OK. That's honest talk. I hope you don't get more offended than you already are, Frank. I think a lot of people like Tar, myself included. I've been using it for a long time, I never had any problems. But then I read the documentation. Jens.
kelvin@thed.uk22.bull.com (Kelvin Hill) (06/20/91)
In <1377@dcl-vitus.comp.lancs.ac.uk> arb@comp.lancs.ac.uk (Andrew Brooks) writes: >How do you recover broken directories? By copying everything you can off the damaged disk. Formatting it using hform. Copying everything you saved back to the now clean disk and finally delving through 100's of diskettes to find your last backup or original of the broken directory. :-( Kelvin. -- Kelvin J. Hill - BULL HN Information System Ltd, Hounslow, England, UK. Internet - kelvin@thed.uk22.bull.com | UUCP - kelvin@cix.compulink.co.uk "" kelvin@kelvin.uk22.bull.com | AMPRnet - kelvin@g1emm.ampr.org
kelvin@thed.uk22.bull.com (Kelvin Hill) (06/20/91)
In <FL.91Jun19093040@pierre.tools.uucp> fl@tools.uucp (Frank Lancaster) writes: >tar will remind you if called with no parameters to READ THE DOCUMENTATION FILE >and THAT I WILL TAKE NO RESPONSIBILITY FOR ANY DATA LOSS DUE TO THE USE OF THIS >PROGRAMME. I never said I *did* hold anyone responsible. I do (given the evidence) hold the program 'tar' responsible. If I'd wanted to hold anyone personally responsible, I would not have made an open mailing. I accepted the risks associated with any public domain software, but I do feel I have a duty to others using the same software to warn them that I have had a minor disaster. They can then decide if they wish to carry on using that software. [ stuff deleted ] >useful utility. But as people who have some kind of trouble using it or with >their hard disc always seem to see the fault in the programme I will now >stop supporting it. I am fed up! Some people would probably write to AT&T and >say that UNIX has a bug because if you rm -rf * it deletes all your files >without saying anything. It was a bad idea that tar was released with >submit/extract without the documentation, but I was preparing a release for If 'rm -rf *' does what it's documented to do, but is misused, thats one thing. If 'tar' on my Unix system had destroyed the hard disk I was saving *from*, I probably would write to AT&T (at the very least as a warning that there seemed to be a problem). I agree about the lack of documentation with the Submit/Extract release. Would it have told me that my disk would get corrupted by using the command line I used? This was not and was never intended to be a personal flame. I'm sorry that it seems to been have taken as such. Kelvin. -- Kelvin J. Hill - BULL HN Information System Ltd, Hounslow, England, UK. Internet - kelvin@thed.uk22.bull.com | UUCP - kelvin@cix.compulink.co.uk "" kelvin@kelvin.uk22.bull.com | AMPRnet - kelvin@g1emm.ampr.org
seifert@diku.dk (Michael Seifert) (06/20/91)
fl@tools.uucp (Frank Lancaster) writes: >tar will remind you if called with no parameters to READ THE DOCUMENTATION FILE >and THAT I WILL TAKE NO RESPONSIBILITY FOR ANY DATA LOSS DUE TO THE USE OF THIS >PROGRAMME. >I must say that I myself use tar on regular basis and I do not have any problems >anymore. The bug that could delete some or all of your hard disc was removed >ages ago. If you read the history section in the documentation you would have >realised this. >I released the tar programme into the public domain because I thought it a very >useful utility. But as people who have some kind of trouble using it or with >their hard disc always seem to see the fault in the programme I will now >stop supporting it. I am fed up! Some people would probably write to AT&T and >say that UNIX has a bug because if you rm -rf * it deletes all your files >without saying anything. It was a bad idea that tar was released with >submit/extract without the documentation, but I was preparing a release for >comp.binaries.acorn with some changes suggested by several users. This will >now not be done. You can buy a commercial backup programme and sue the >company if it doesn't work, I have a heavy work load (some people do have to >work for a living) and do not have the time to support a PD programme which >is supposed to satifies everyone's idea of ease of use and safety. >Frank Lancaster No need to be upset - nobody has accused you of anything. It is a fact that some (older?) versions of tar likes to garble hardiscs and archives, and I see no reason why you should reply in this tasteless manner. It is only fair that warnings are posted to this group, be they justified or not. Regards, Michael Seifert seifert@freja.diku.dk
fl@tools.uucp (Frank Lancaster) (06/24/91)
Well, the heat has now steamed off... The problem with these 'bug' reports is that I am mostly unable to reproduce them. If someone reports that his hard disk has been mangled, I try to understand what happened and try to reproduce it. But up to now I haven't a clue as how something like breaking directories should be caused by tar. The one time this happened to me wasn't with tar. I did a *compact before I wanted to do a backup (I don't know why, maybe I'm becoming senile). After the compact about 20% of the hard disc was garbage. I was somewhat upset. This happened twice without using tar, only using the OS. It was with 80MB hard discs. Once even the disk map got corrupted but there were no bad sectors on the disc. With a 20MB disc I never had problems. I have the feeling that the problem may be in the adfs code. Tar only reads and writes files and creates directories all with OS routines (actually mostly the C library). Frank Lancaster