Re: A loop mounted FAT filesystem.

[Klaus <klaus.doering999@gmail.com>]

On 19/06/13 17:46, peasthope@shaw.ca wrote:
> *	From: Klaus <klaus.doering999@gmail.com>
> *	Date: Tue, 04 Jun 2013 08:48:22 +0100
> > I didn't understand why you used the -"C" option in
> > this case instead of just giving the device name ?
>
> My objective is to have a FAT filesystem residing in an ext3
> file in wheezy.
>
> Consequent to the difficulty with "mkdosfs -C ..." I've tried
> working through a case similar to "Floppy Disk Images With FAT16".
> http://wiki.osdev.org/Loopback_Device#Floppy_Disk_Images_With_FAT16
>
> # 1. Make the empty image file.
> peter@dalton:~$ dd if=/dev/zero of=FATholder bs=512 count=288000
> 288000+0 records in
> 288000+0 records out
> 147456000 bytes (147 MB) copied, 4.55382 s, 32.4 MB/s
>
> # 2. Set it up for mounting.
> root@dalton:/home/peter# losetup /dev/loop0 FATholder
>
> # 3. Create the FAT filesystem.
> root@dalton:/home/peter# mkfs.vfat
> mkfs.vfat 3.0.13 (30 Jun 2012)
> Loop device does not match a floppy size, using default hd params
>
> # 4. Show that the user is allowed to mount the image;
> root@dalton:/home/peter# grep loop /etc/fstab
> /dev/loop0  /home/peter/FATmount  vfat  defaults,noauto,user  0       0
>
> # ... and mount it.
> peter@dalton:~$ mount /dev/loop0
> peter@dalton:~$ mount | grep loop
> /dev/loop0 on /home/peter/FATmount type vfat (rw,nosuid,nodev,noexec,relatime,ui
> d=1000,gid=1000,fmask=0022,dmask=0022,codepage=cp437,iocharset=utf8,shortname=mi
> xed,errors=remount-ro,user=peter)
>
> # 5. Confirm that the virtual FatFS can be written to.
> peter@dalton:~/Work$ cp rawrite.exe ~/FATmount
> peter@dalton:~/Work$ ls -l ~/FATmount/raw*
> -rwxr-xr-x 1 peter peter 12702 Jun 19 09:37 /home/peter/FATmount/rawrite.exe
>
> Conclusion: success in five steps is better than failure in one step.
>
> Thanks for the feedback,        ... Peter E.

$ sudo mkdosfs -C test-mkdosfs-file 1440
mkdosfs 3.0.16 (01 Mar 2013)

$ ll test*
-rw-r--r-- 1 root root 1474560 Jun 19 20:52 test-mkdosfs-file

$ mkdir mnt

$ sudo mount -o loop -t vfat test-mkdosfs-file mnt/

$ ll mnt
total 0

$ sudo cp mini_ITX_spec_V1_1.pdf mnt/

$ ll mnt
total 379
-rwxr-xr-x 1 root root 387424 Jun 19 20:54 mini_ITX_spec_V1_1.pdf

$ mount
(...)
/home/klaus/tmp/test-mkdosfs-file on /home/klaus/tmp/mnt type vfat 
(rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=utf8,shortname=mixed,errors=remount-ro)

$ df
Filesystem     1K-blocks     Used Available Use% Mounted on
(...)
/dev/loop0          1424      379      1045  27% /home/klaus/tmp/mnt


Did you ever find out why this didn't (doesn't?) work for you?
--
Klaus