Jesse Phillips Wrote:

> On Sun, 02 Mar 2008 17:02:33 -0500, Ty Tower wrote:
> 
> > Lars Ivar Igesund Wrote:
> > 
> >> Jesse Phillips wrote:
> >> 
> >> > I'm interested in knowing why FileRoots.list() uses /etc/mtab for its root folders in linux? To my knowledge Linux only has one root and if anything its sub directories would be considered the roots. I just don't see the point of using mtab, but then again I'm looking at it from how file managers look at the system.
> >> 
> >> The unix root / isn't the most useful thing to ask for, thus mtab is used to show all mounted devices.
> >> 
> >> --
> >> Lars Ivar Igesund
> >> blog at http://larsivi.net
> >> DSource, #d.tango & #D: larsivi
> >> Dancing the Tango
> > 
> > ftab mounts the original devices and empowers them mtab looks after the devices added later ie plugging in the usb stick or something like that
> > 
> > is the  file used in that sort of context?
> 
> it can't, it reads the file when called, so it will only get already mounted devices, a file change listener of some sort would have to be created to track later mounted devices.
> 
> For me must of the mounted items in mtab are useless, but it can be easily version'd out as needed.


Probably should add (perhaps you already know)
 /etc/fstab          Lists the filesystems mounted automatically at startup  by the mount -a command (in /etc/rc or equivalent startup file).

 /etc/mtab         A list of currently mounted file systems. Setup by boot scripts and updated by the mount command.

So if you want a list of what's mounted right now mtab is the place to go

Reply to ty,

> So if you want a list of what's mounted right now mtab is the place to
> go
> 

isn't there something in /proc that grovels in the kernel? I would rather get info from the kernel than a state file updated by some apps. (I don't have a *nux box handy to try with)

Ty Tower wrote:
> BCS wrote:
> 
> 
>>Reply to ty,
>>isn't there something in /proc that grovels in the kernel? I would
>>rather get info from the kernel than a state file updated by some
>>apps. (I don't have a *nux box handy to try with)
> 
> 
> Heh heh ! This is classic . Pardon my humorous response. When we
> grovel in the dirt we get down and dirty lying and squirming in the
> dirt.
> 
>  I don't know but you probably are saying that there is something in
> the kernel that returns that information as well.

Now that I have a Linux box handy...

take a look at the /proc/mounts file. Mine gives this:

$ cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw 0 0
/proc /proc proc rw 0 0
usbdevfs /proc/bus/usb usbdevfs rw 0 0
none /dev/pts devpts rw 0 0
none /dev/shm tmpfs rw 0 0

IIRC this is a file in a "fileystem" that is actually a device for reading kernel and system state. This reflects the actual current state of the system, not the last thing written to some file.

> I can't say . I am
> not that familiar with the kernel but my understanding is
> that /etc/mtab is updated by the kernel as each device is added or
> removed instantly.

Potentially someone could over wright /etc/mtab with junk. Not likely but...

> I don't think any applications act on it except
> maybe Hal.
> 
> And did you mean "*nix"  as Unix/Linux box ,I think so  
> 

yup

On Tue, Mar 4, 2008 at 7:04 AM, BCS <ao@pathlink.com> wrote:
>  isn't there something in /proc that grovels in the kernel? I would rather
>  get info from the kernel than a state file updated by some apps. (I don't
>  have a *nux box handy to try with)

On Linux, sure. But that wouldn't be portable at all, /proc is quite Linux-specific.

Anders

BCS Wrote:
> Now that I have a Linux box handy...
> 
> take a look at the /proc/mounts file. Mine gives this:
> 
> $ cat /proc/mounts
> rootfs / rootfs rw 0 0
> /dev/root / ext3 rw 0 0
> /proc /proc proc rw 0 0
> usbdevfs /proc/bus/usb usbdevfs rw 0 0
> none /dev/pts devpts rw 0 0
> none /dev/shm tmpfs rw 0 0
> 
> IIRC this is a file in a "fileystem" that is actually a device for reading kernel and system state. This reflects the actual current state of the system, not the last thing written to some file.
> 
> > I can't say . I am
> > not that familiar with the kernel but my understanding is
> > that /etc/mtab is updated by the kernel as each device is added or
> > removed instantly.
> 
> Potentially someone could over wright /etc/mtab with junk. Not likely but...
> 
>  > I don't think any applications act on it except
> > maybe Hal.
> > 
> > And did you mean "*nix"  as Unix/Linux box ,I think so
> > 
> 
> yup

Good stuff - I am learning each day Thanks

Reply to ty,

> Good stuff - I am learning each day Thanks
> 

your wecome :)