johnk@chinet.chi.il.us (John Kennedy) (10/16/88)
Here's a question concerning Microport Unix (SYS V/AT), and maybe it's a Unix question in general. A couple of weeks ago, I backed up everything on my disk for the purpose of repartitioning between DOS and Unix. I used a find ... | cpio -ocv > /dev/rdsk/0s24. This is the way I had always done backups. Maybe I should have used tar or whatever, but that's water over the dam. When I went to restore the files, with a cpio -icdumv < /dev/rdsk/0s24, the first few disks read okay, but then the "out of phase. get help" message appeared. Apparently the disks were not written correctly. Going back to the previous backups I had done, I found that many of them, too, were unreadable. This leaves me in a pretty sad state. I am assuming that some sort of header information is trashed, but that there also could be some good images of some files on the floppies. I have been to read the disks to a file by using dd, and what I was wondering if anyone might know, is there some way of modifying that file, and extracting information about any good files and salvaging some data? Please email replies to !chinet!johnk. Thanks.
zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff) (10/17/88)
In article <6794@chinet.chi.il.us> johnk@chinet.chi.il.us (John Kennedy) writes: > >When I went to restore the files, with a cpio -icdumv < /dev/rdsk/0s24, >the first few disks read okay, but then the "out of phase. get help" >message appeared. Apparently the disks were not written correctly. You can use the fixcpio program or I believe that you can use afio. Sources for both should be available from archive sites. -- Jon Zeeff Branch Technology, umix!b-tech!zeeff zeeff@b-tech.ann-arbor.mi.us
hulsebos@philmds.UUCP (Rob Hulsebos) (10/18/88)
In article <6794@chinet.chi.il.us> johnk@chinet.chi.il.us (John Kennedy) writes: >When I went to restore the files, with a cpio -icdumv < /dev/rdsk/0s24, >the first few disks read okay, but then the "out of phase. get help" >message appeared. Apparently the disks were not written correctly. Yes, I've seen this bug too. Apparently, when 'cpio' writes to its output- device but gets an error, it just cancels writing the current file without giving an error, and continues with the next file. But because a header is already written to floppy, and the file written after the header does not match the length noted in the header, 'cpio' gets out-of-sync when it reads the disk back :-( Tar behaves better in this aspect. To my humble opinion, 'cpio' should at least give an error-message. As it is now, you're required to read back disks written with 'cpio' immediately after they have been made, unless you're 100% sure that the disks are OK. In article <4873@b-tech.ann-arbor.mi.us> zeeff@b-tech.UUCP (Jon Zeeff) writes: >You can use the fixcpio program or I believe that you can use afio. >Sources for both should be available from archive sites. The best solution would be to fix 'cpio'. ------------------------------------------------------------------------------ R.A. Hulsebos, Philips I&E Automation Modules ...!mcvax!philmds!hulsebos Building TQ-III-1 room 11 phone: +31-40-785723 Eindhoven, The Netherlands "f77 hello.c; a.out" works!
bzs@xenna (Barry Shein) (10/23/88)
The problem is that cpio is not a backup utility and it's irresponsible to use it as such. This problem is only one of several fatal problems with using cpio to do backups. For those who have nothing else, my sincerest sympathies, you're driving on ice with bald tires, I've been there... -Barry Shein, ||Encore||