I have to use a lot of CDs and I need to insert them, see their contents and change them quickly. How can I optimize their mounting and unmounting? Will there be a problem if I just remove them from drive and change them without clicking on eject option from their icon on desktop?

Hi rng,

We usually use mount and umount options where we want the data in cache to be written on the device. For example if you connect a USB drive and copy something onto it then it is always advisable to umount it instead of directly removing it because the data is actually written just before the device is unmounted. This is applicable in the situation where the device is mounted with async option.

CD-ROM is mounted as read only device so there shouldn't be a problem if you directly change the CD instead of ejecting it and then removing it. But if you go by procedure then it is good to eject and then insert the new one. The reason being even if you remove the CD the system for a fraction of time keeps the old image and you might get invalid handle error if you directly put in the new CD.

Thanks for the info.

In addition, the drive will probably be locked so you can not eject via it's push button unless the disk is unmounted.

I have to work in a windoz program thru wine which reads CDs. I have set cdrom folder in wine to /cdrom. But CDs are mounted in a subfolder of /media folder created according to label of CD, eg /media/123456. Hence, with every change of CD, I have to give commands 'sudo umount /cdrom' and 'sudo mount /dev/sr0 /cdrom'. I windoz, one can simply remove CD and insert second CD and continue work in program.

How can I speed up mounting of CD?

If I enter following line in /etc/fstab, will ubuntu always mount CDs on /cdrom (even later once system is running and when I change CDs)?

Nope, /etc/fstab is referred by the system only at the time of booting. If you put the CD in and the boot up your first then it will mount that CD to /cdrom directory. However, when you will change CDs it will mount to default mount point which is /media unless you specify manually to mount at some other location.

No so! I have this in my fstab:
/dev/sdb1 /media/usb ext2 noauto,noatime,users 0 0
and all my usb memory sticks mount to /media/usb when inserted (auto mounting is on).

@ DavidMcCann,

I tried it for my CDs and it is unable to mount CD until I run mount -a. When you say automounting is on are you talking about autofs?

By "automounting", I mean the desktop is set to mount any removable media when they are inserted.

By default, ubuntu automounts inserted CDs on a folder created in /media according to the label of the CD.

I tried putting following line for /dev/sr0 (cdrom) in /etc/fstab in ubuntu:
It automounts only if a CD is there at boot time (gives an error message if no CD is present in the drive). There is no automounting if cd is inserted later on (not even on /media/cd-label folder).

What you did wrong there was to put "auto" in the 4th column of fstab when you should have put "noauto".

I now have tried 'noauto' also but it does not work.

I found the answer on following sites. This line in /etc/fstab works well- automounts cd on /media/cd folder:
https://bbs.archlinux.org/viewtopic.php?id=115424
http://forum.winehq.org/viewtopic.php?p=58359#58359