[9fans] writing with cdfs

[9fans] writing with cdfs

[anothy]

i've got a NEC CD-RW drive. it reads fine - i can plop in a
cd, mount a file system from it, whatever. writing is failing
in a way i don't understand. and no, i'm not using the non-
standard sized disks i asked about earlier; i went out and
picked up a few standard sized ones to test. no change.

as soon as i try to write to /mnt/cd/wa, cdfs hangs. further
request to it hang, as well. subsequent 'ls /mnt/cd' won't
return, nor will 'cat /mnt/cd/ctl'. in an effort to figure
out what's going on, i'm running 'cdfs -v'. in /tmp/cdfs.log
there's loads of lines exactly like this one:
	dat read: i/o error: cmd 0x43
these show up even when i'm just reading. when i write a
track, say with 'cp a000 /mnt/cd/wa', i get a series of
lines like this:
	985793380254305823: write 12 at 0x0
	985793382932935724: write 12 at 0xc
	[...]
	985793389322790504: write 12 at 0x708
	985793389348130160: write 12 at 0x714
and the drive's making encouraging noises. after the last one
(0x714), the drive stops, nothing's printed into the log, and
i get the frozen behaviour described above. i let it sit for
several hours (i was on my way out anyway) with no change. i
was writing seven tracks (about half an hour of audio, 309MB)
into the device. i've tested it trying to write a single 3
minute song. same behaviour.

when this hangs, it _really_ hangs. cdfs is un-killable, as
is any process talking to it, like the cat and ls above.
after rebooting (since cdfs locks the device), i find an
overly-large single audio track on the disk (>780MB on a
standard CD?). the contents of this file don't seem to be
anything recognizable.

i suppose it's possible that this is a hardware issue. i've
never used this particular drive. but it's brand new, so i
consider that at least unlikely.
-α.

Re: [9fans] writing with cdfs

[Scott Schwartz]

> when this hangs, it _really_ hangs.  cdfs is un-killable, as
> is any process talking to it, like the cat and ls above.

Speaking of that, one of my pet peeves is that a misbehaving file server
can make application processes uninterruptably block in read or write.
It reminds me of the early days of NFS.

Re: [9fans] writing with cdfs

[Boyd Roberts]

"Scott Schwartz" <schwartz@bio.cse.psu.edu> a crit dans le message news:
20010330033533.17514.qmail@g.bio.cse.psu.edu...
> It reminds me of the early days of NFS.

reminds me of badly written streaming tape drivers.