Re: Re (2): mkdosfs -C ...

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

On 05/06/13 02:46, peasthope@shaw.ca wrote:
> Since the original trial, the system was upgraded from
> Squeeze to Wheezy.
>
> From:	Klaus <klaus.doering999@gmail.com>
> Date:	Tue, 04 Jun 2013 08:54:46 +0100
> > Increase block count a little, and hey presto:
> > $ sudo mkdosfs -v -C FatFile2 1024
> > mkdosfs 3.0.16 (01 Mar 2013)
> > FatFile2 has 64 heads and 32 sectors per track,
> > logical sector size is 512, ...
>
> In Wheezy I fare no better than in Squeeze.
> root@dalton:~# mount | grep sdb
> /dev/sdb1 on /media/usb0 type vfat (rw,nodev,noexec,noatime,nodiratime,sync,fmas
> k=0022,dmask=0022,codepage=cp437,iocharset=utf8,shortname=mixed,errors=remount-r
> o)
> root@dalton:~# ls -ld /media/usb0
> drwxr-xr-x 3 root root 16384 Jun  4 18:12 /media/usb0
> root@dalton:~# mkdosfs -v -C /media/usb0/FatFile 1024
> mkdosfs 3.0.13 (30 Jun 2012)
> mkdosfs: unable to create /media/usb0/FatFile
>
> From:	Klaus <klaus.doering999@gmail.com>
> Date:	Tue, 04 Jun 2013 08:48:22 +0100
> > ... didn't understand why you used the -"C" option in this case
> > instead of just giving the device name ?
>
> The intention is to make an empty file occupying the whole
> partition.  Then another filesystem can be mounted on that
> empty file; or "another filesystem can occupy that file" might
> be better terminology.  The -C option is explained briefly
> by man mkdosfs.  Loop device is explained in Wikipedia.
>
> http://en.wikipedia.org/wiki/Loop_device
>
> Regards,           ... Peter E.

Peter,

Here are test on a newly (re-)created partition on a USB stick, and I'm 
running SID. After creating the

$ sudo mkdosfs -v -n TEST_FAT16 -C /media/user/TEST 1024
mkdosfs 3.0.16 (01 Mar 2013)
mkdosfs: unable to create /media/user/TEST

$ sudo mkdosfs -v -n TEST_FAT16 -C /media/user/TEST/test-mkdosfs-file2 1024
mkdosfs 3.0.16 (01 Mar 2013)
/media/user/TEST/test-mkdosfs-file2 has 64 heads and 32 sectors per track,
logical sector size is 512,
using 0xf8 media descriptor, with 2048 sectors;
file system has 2 12-bit FATs and 4 sectors per cluster.
FAT size is 2 sectors, and provides 502 clusters.
There is 1 reserved sector.
Root directory contains 512 slots and uses 32 sectors.
Volume ID is 32523ae6, volume label TEST_FAT16 .

$ sudo mkdosfs -v -n TEST_FAT16 -C /media/user/TEST/test-mkdosfs-file2 1024
mkdosfs 3.0.16 (01 Mar 2013)
mkdosfs: unable to create /media/user/TEST/test-mkdosfs-file2

As you can see, I get the same error as you report under two conditions, 
(1) when I specify a directory instead of a file to the "-C" option, and 
(2) when the file already exists. Any help?

Have you tried the mkdosfs on a file located somewhere else, e.g. in a 
tmp folder on your hdd?
Since you have mounted the USB device, there'll be a filesystem on there 
already. Have you tried writing to it, like "touch /media/usb0/testfile"?
Just for trouble shooting, have you tried to create a DOS filesystem 
directly on the partition, i.e. without the "-C" option ?

--
Klaus