[ILUG] Confused mount ?

[Niall O Broin]

I wanted to copy a CD so I pressed the eject button my IDE DVD player to
insert the new CD. However, the old one was still mounted. I thought the
drive was locked when a CD was mounted ? But no harm done - I simply
umounted and mounted again. The sequence is illustrated below, which I cut
and pasted from an xterm, slightly edited for clarity.


niall at bagend:~ >mount /cdrom
mount: /dev/cdrom already mounted or /media/cdrom busy
mount: according to mtab, /dev/hdd is already mounted on /media/cdrom

niall at bagend:~ >df /cdrom
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/hdd                653208    653208         0 100% /media/cdrom

niall at bagend:~ >umount /cdrom
niall at bagend:~ >mount /cdrom
niall at bagend:~ >df /cdrom
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/hdd                600526    600526         0 100% /media/cdrom

niall at bagend:~ >umount /cdrom

niall at bagend:~ >sudo dd if=/dev/hdd of=/mnt/xyzzy.iso bs=100k

niall at bagend:~ >sudo mount -o loop /mnt/xyzzy.iso /mnt1

niall at bagend:~ >df /mnt1
Filesystem           1k-blocks      Used Available Use% Mounted on
/mnt/xyzzy.iso          653208    653208         0 100% /mnt1



Do you see the problem here ? I dd'ed the second CD to the file yet when I
loopback mount the iso image, the filesystem appears to have the size of the
first CD and an ls of the root of that filesystem show its contents to be
the same as the first CD. Something stinks here :-( Yet an ls of the actual
iso image shows that its size corresponds with the size of the filesystem
mounted from the second CD.


niall at bagend:~ >ls -l /mnt/xyzzy.iso
-rw-r--r--    1 root     root     615354368 Nov 12 11:46 /mnt/xyzzy.iso


No real harm done, as I'll simply make a new ISO which I'm doing now, but
there's definitely something awry. It started with my being able to eject a
mounted CD and went downhill from there. Any ideas ?


Niall


P.S. Interactive response on my box suffers when I do such a dd. I've an
idea it's IDE related. Any more ideas ?