Date: Fri, 19 Sep 2008 05:35:59 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: freebsd-stable@FreeBSD.ORG, talon@lpthe.jussieu.fr, jhb@FreeBSD.ORG Subject: Re: floppy disk controller broken Message-ID: <20080919123559.GA45054@icarus.home.lan> In-Reply-To: <200809190955.m8J9t5mE092126@lurza.secnetix.de> References: <20080918183250.GA48347@lpthe.jussieu.fr> <200809190955.m8J9t5mE092126@lurza.secnetix.de>
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On Fri, Sep 19, 2008 at 11:55:05AM +0200, Oliver Fromme wrote: > Michel Talon wrote: > > Oliver Fromme wrote: > > > Michel Talon wrote: > > > > Moreover, trying to write to the floppy: > > > > niobe# dd if=/dev/zero of=/dev/fd0 conv=noerror > > > > dd: /dev/fd0: Input/output error > > > > 5+0 records in > > > > 4+0 records out > > > > 2048 bytes transferred in 4.054404 secs (505 bytes/sec) > > > > > > > > I don't expect such result. Traditionnally writing works, while reading > > > > may fail. > > > > > > Maybe I misunderstand what you're saying, but ... > > > When I try to write to a floppy that has *not* been > > > successfully formatted, I very much expect to get > > > Input/output error. Anything else would be a bug. > > > > The floppy has certainly be formatted, in the past. Perhaps i > > remember badly, i have not used floppies since years, but > > in this case the behavior with Windows, Linux and ancient FreeBSD > > was that you could write to the floppy, but could encounter errors > > while reading. > > Since you mentioned "ancient" FreeBSD, I assume that was > using buffered block devices, when FreeBSD still supported > them? That sounds right -- again, if my memory hasn't failed me... > Nowadays /dev/fd0 is a character device which is > unbuffered, i.e. your dd(1) command goes straight to the > disk, and if the drive reports an error (typically sync > mark not found if the floppy is unformatted), it goes back > up to dd(1) immediately and you get Input/output error. Ah ha! Evolution has occurred. Thanks for educating me. :-) -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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