Re: [Mtools] Formatting large capacity SD cards

[Alain Knaff]

Simon Large wrote:
> Hi folks,
>
> I am trying to get a 4GB SD card working on Windows and Linux. At the
> moment a card formatted on Windows will not mount using kernel 2.6.16.
> The help doesn't give many clues about how to pick the right number of
> heads/tracks/sectors/sector-size. Any ideas?

Normally, the vfat FS should mount the card no matter what number of 
heads, tracks, sectors are used to format it.

Do you get any error messages when attempting to mount the card? Kernel 
error messages are displayed using dmesg.

Also, be aware that I only do mtools. The in-kernel Vfat and Fat 
filesystems (that are used for mounting) are handled by Werner 
Almesberger, as far as I known.

Also, you should only access cards or disks using one method at a time. 
That is, never use mtools on a mounted card.

> I found an error in the output of minfo where it gives an mformat
> command line to use.
>
> (values read back from a 256M card)
> sectors per track: 63
> heads: 255
> cylinders: 32
> sector size: 512 bytes
> hidden sectors: 99
>
> mformat command line: mformat -t 32 -h 255 -s 63 -H 99
>
> I think that should be: mformat -t 32 -h 255 -n 63 -H 99 -S 2
>
> Simon

Yes, indeed. Minfo leaves away the sizecode of the mformat command line. 
However, in the common case of 512-byte sectors, the sizecode is 
redundant anyways, as it is the default.

However, I'll add the feature in the next patch (display sizecode if 
different from 2)

Regards,

Alain