Xref: utzoo comp.sys.att:7011 unix-pc.general:3333 Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!dptg!att!shuxd!attdso!galaxia!cals01!cals From: cals@cals01.NEWPORT.RI.US (Charles A. Sefranek) Newsgroups: comp.sys.att,unix-pc.general Subject: Re: UNIXpc crash & can't restore cpio - HELP! (long) Keywords: disk crash cpio panic Message-ID: <461@cals01.NEWPORT.RI.US> Date: 19 Jul 89 00:31:36 GMT References: <588@holin.ATT.COM> Reply-To: cals@cals01.Newport.RI.US (Charles A. Sefranek) Distribution: na Organization: My Very Own Castle, Portsmouth RI Lines: 64 In article <588@holin.ATT.COM> doc@holin.ATT.COM (David Mundhenk) writes: > > ... Then I tried to restore >my cpio backup (saved with cpio -ocvumB>/dev/rfp021 >on 10 sector floppies). On disk #3, I got the message: > >"I/O failure on header: I/O error >Can't read input; aborting." > ... > >W H A T G I V E S ? > >This is the first time I've had trouble with a cpio backup on this >system. Could it be a bad floppy, are my heads dirty, or what? > I ran into this problem too! It drove me nuts until I finally found out what was going on. I remember other people on the net complaining about this too, usually blaming cpio. I should have suspected something when I bought a BIG batch of those cheap floppies and hardly ever found a bad one... If you format floppies with the ua (and even if you don't) BE CAREFUL - the "surface test" it runs DOESN'T ALWAYS FIND BAD FLOPPIES!!! Even using iv won't find them. The only reliable method I've found is to use iv with the -l option to force 10 passes of the surface test. This takes a LONG time but its worth it. The command to use is: iv -iwl /dev/rfp020 descriptionfile (See the manual for descriptionfile). Naturally you have to follow this with the appropriate mkfs command if you want to put a file system on it (not necessary for cpio diskettes). After I discovered this, I wrote my own shell script to format floppies and guess what -- I found LOTS of previously "good" floppies that are actually bad. I went through all my backups weeding them out. Keep an eye on the /usr/adm/unix.log file when you are formatting floppies. If you format a floppy that has never been formatted before you should typically get four entries for it. If you reformat a previously good floppy, you should get NO entries. If you get entries for a previously formatted floppy, and it appears to format OK, then it encountered soft errors during the formatting - I would put it aside and only use it for non-critical info. The system will automatically delete the unix.log file if it gets too big (somewhere around 10K bytes). Oh, by the way, if you understand how to create the descriptionfile per the manual above, you can format floppies with 10 sectors per track, and 42 cylinders; that's right 42 cylinders, not just 40!!! This gives me an extra 40 blocks on each floppy. Can't guarantee it'll work on everybody's drives, but I know at least two other people who do the same. (Don't try for 43 cylinders, the drive makes an awful crunch when it hits the stops!) -- Charlie Sefranek cals@cals01.NEWPORT.RI.US UUCP: {rayssd,xanth,lazlo,mirror}!galaxia!cals01!cals Alt.: c4s@rayssdb.ray.com {sun,decuac,gatech,necntc,ukma}!rayssd!rayssdb!c4s