Basics about partition/mounting sticky?

Alone today I saw at least three threads by people who have not the slightest idea about the Unix/Linux directory tree, about what mounting is (one mounted a new partition on /tmp on the flight and did not understand why he could not unmount). Also the heritage of the MS/DOS idea about all partitions having their own root (still not developed to something better in Vista I think) seems to get stuck in peoples minds.

Now my question is could a sticky or an SDB (or something else) help here. I am willing to contribute, but the first question is do you folks think yes/no and when yes where?

Sounds good to me hcvv,if you do decide to do it, put it inthe How-to’s section.Or you could put it in the SDB as well. Both would be very gratefully received

Andy

I will give it a try. May take some time. When I think l;onger about it (and reading a new thread :slight_smile: ) a few words about what an extended partition is may be usefull also.

I will first start on my own system (i always need to rshuffle pargraph, etc.) and when I think there is at least a bit of usefull info I will then try to put it into SDB/Howto/… , so that everybody can comment/change it. May be I need some help with the SDB.

I decided for an SDB because I (and others) can edit there when needed. I am a person who always sees something that could be a bit better after three days and the five minutes of the Forum is not enough for that.

It is here: SDB:Basics of partitions, filesystems, mount points - openSUSE

Now apart from other people taking the Wiki way and improving this document, you may also comment here and leave it to me to implement your wishes. (If I refuse to do so you can still do it the Wiki way).

Other comments (e.g. how to bring these SDB documents closer to the newbee asking questions on the Forum) are also welcome.

A full “Petje af, meneer Henk” !!! It’s still a bit technical (not for me, but for the ones looking for help), but very complete. Cheers !!!

Thanks for the voting points coming from Groningen :wink: (this is Lochem btw).

When somebody could tell where the technical part could be made more understandable for the noob, I would be glad.

OTOH making the story to long could people refrain from reading it. It is always the problem that people do not want to invest some time to gather knowledge because such investment saves much more time later.

I’ve seen many posts in the forum regarding removable devices, that direct the user to describe them in fstab, which may lead to conflicts, IINM.

AFAIK those devices get described in /etc/mtab, just like fstab but created on the fly (by udev?).

It may be a good idea to insert a note about this in the fstab section, or something like that.

A lot of external drives today are USB, and as such are seen as removable drives, like pen drives. I think.

Thanks for this. I will will try to understand what is going on in this subject ad then change the document. I will report back here.

I am back already.

When reading man mount you will see that /etc/mtab is the “table of mounted file systems”. In other words the same as what will be displayed when you give the mount command (but with a different lay-out.):

boven:~ # cat /etc/mtab
/dev/sda2 / ext3 rw,acl,user_xattr 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
debugfs /sys/kernel/debug debugfs rw 0 0
udev /dev tmpfs rw 0 0
devpts /dev/pts devpts rw,mode=0620,gid=5 0 0
/dev/sda3 /home ext3 rw 0 0
nfsd /proc/fs/nfsd nfsd rw 0 0
boven:~ # mount
/dev/sda2 on / type ext3 (rw,acl,user_xattr)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
debugfs on /sys/kernel/debug type debugfs (rw)
udev on /dev type tmpfs (rw)
devpts on /dev/pts type devpts (rw,mode=0620,gid=5)
/dev/sda3 on /home type ext3 (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
boven:~ #

This stresses the fact that all these mass storage devices just mimic the old fashioned revolving hard disk. Seen from the system (from a certain level, the level that is of importance to the system manager) they are all the same. Features like udev (and hal) see that dynamic connecting/removing is handled properly.

An answer to your questions:
a) /etc/mtab is not for on the fly added disks only, but for all mounted partitions;
b) it is maintained by mount and not by udev;
c) the kernel will signal the udev-deamon about devices that come and go, udevd will, among other things, create the device special files and call mount (and signal the hal-deamon).
IMHO the whole kernel-udev-mount-hal cycle is to much in-depth for the document. For the document audience I have in mind, it is enough to know what mounting is, what you can mount, where you can mount, how you can see what is mounted, etc. May be a remark about the automaticaly mounting by udevd will be usefull. I will have a look where that fits in.

About udev: udev - Wikipedia, the free encyclopedia

Good info, thanks.

Mostly my point is about a new user asking: where’s my usb drive? I just inserted it and … etc, etc., and someone directs the user to check fstab, the user doesn’t find the drive in it, someone tells him to add it do fstab, and the mess is done.

Of course, all mounts are in mtab. In a sense it’s more important than fstab (in a sense, mind you), as there’s a lot of usb thingies nowadays.

Correct. fstab is a configuration file and mtab is a status file.

The problems you describe with people not knowing where there USB devices go are real. ATM I am updating myself on this (what does udev, who does mount and why does it mount where it mounts, etc). I will incluse about this in the document. (but first I go for a nice walk, beautifull weather here :wink: ).

Always a good idea :slight_smile:

You also participated in the very nice discussion in Why mounts HAL in /media? - openSUSE Forums.
I added a chapter to the SDB as a result of this: SDB:Basics of partitions, filesystems, mount points - openSUSE.

Thanks for your cooperation.