formating external USB hard drive

[François Patte]

Tim a écrit :
> On Fri, 2006-01-27 at 15:03 +0100, François Patte wrote:
> 
> 
>>I have a USB hard drive and 3 questions:
>>
>>1- I suppose that this hd is dos-formatted by default. Is it because 
>>this that I had a problem of file size limitation? I couldn't create a 
>>file more than 4.2Gb.
> 
> 
> I don't know the filesize limit for DOS, but I thought it was less than
> that.  If you need to store large files, it's well worth your while to
> find out what the size limits are for the filing systems available to
> you (and use the one best suited).

4Gb is the limit for fat32 file system, according to some google
information....

So I tried to format my usb hard drive with ext3 file system and I could
store 8Gb file. It seems that the limit with ext[2,3] file system is
2Tb. OK!

> 
> 
>>2- Is the problem will be the same with an ext3 file system, and will 
>>udev/hotplug/hal recognize and automatically mount the device if I 
>>format it with mkfs.ext3?
> 
> 
> I can't see why not.  Hal cares about hardware being plugged and
> unplugged.  After that comes determining how to mount it.

With ext3 file system, the device is still automatically mounted; so
far, so good!

But:

1- the name has changed: from the brand name (Lacie) of the disk, it has
move to "usbdisk". No harm, but I wonder why!

2- the first time I plugged it in, it was mounted as root.root with only
write permission for root.... I changed the owner and the group without
any problem, but now it is always this name and this group which is used
when the disk is mounted. Where are defined these things? I think that
the disk, once mounted, must have for owner and group the uid and gid of
the user who plugs it, if not we cannot use these kind of disks to
exchange files and directories between different people and machines. It
was the default behaviour when formated has vfat.

Thanks for help.

> 
> If you're about to reformat the drive, and therefor don't have to keep
> contents on the drive, you can test both of the above queries, yourself.

How could I go back to vfat file system? I have only linux machines.


-- 
François Patte
UFR de mathématiques et informatique
Université René Descartes
http://www.math-info.univ-paris5.fr/~patte