Hi!

everytime i insert a cd its contents aren´t shown until i mount it.
do i always have to mount/umount cdrom?

some distros will automatically mount a CD when you insert it. I assume your question applies to Slackware 10.2--I am not familiar with this one. Any clues in Slackware docs?

It really depends on your linux distro.
AFAIK, Mandrake >10 and Kubuntu mount your CD as soon as you try to access it.
It is related to your running kernel (i.e Madrake uses a special file-system technique named "supermount" only present on Mandrake kernels) and/or your desktop environment (i.e. KDE>3.5)

I am working on it, but in some installation guides it is written that the cdrom should be mounted and in some not. I was wondering if there is a universal solution for linux-based systems...

i have 2.4.31 kernel, KDE 3.4.2 (basic configuration for slack 10.2)
but is KDE responsible for mounting?

My observation has been that if it's a Media CD/DVD, it'll automount ... If it's a data CD/DVD (including MP3s), you have to mount it manually.

At least that's 'the Debian way.'

Ok, just to make it clear, the answer is yes. You need to mount a disk, or any storage medium, before you can read or write to its file system. That's what mounting is, after all, connecting file systems. Now, as the others have pointed out, it's possible to set up a system to automatically mount the disk for you when you try to access it, and unmount it for you after a few seconds of inactivity. Supermount does this, as does autofs, and there may be one or two other ways to go about it. (Supermount uses kernel-level code. Autofs OTOH runs as a daemon, but it can be a little more flaky.) Many of the more user-friendly distros are already set up with one of these for you, usually supermount.

That said, there are a couple of situations where mounting is unnecessary. Applications like CD writers access the disk directly from the low-level driver interface and don't need a mounted disk. And music CD's are not mountable, since they do not have a normal file system to mount. Your music player software again uses a lower-level access in order to play the disk.

Video CD's and DVD's and are hybrids. They are encoded to disk using a mountable file system, but playing the actual content works more like a music CD, and doesn't need mounting.

I hope this clears it all up for you.

thank you, very informative

i have one more question (may be a stupid one) how can i (u)mount hotplug devices (like usb flash memory, bluetooth devices etc), no name has been assigned to it in the fstab
does the linux recongnise them? is it safe just to plug them in?

It's only filesystems that need to be unmounted so unless you're using PAN over Bluetooth to mount a remote location, no need to unmount. A USB drive on the other hand, yes you need to unmount it. You can use the sync mount option which is supposed to make it so even if you rip the device out mid-copy most of the data should be alright. That is extremely mind-bogglingly slow though.