(don't write to me personally, I do read the list) On Fri, Jul 29, 2005 at 04:56:43PM +0530, Srinivas G. wrote: > We have developed a Block Device Driver to handle the flash media > devices in Linux 2.6.x kernel. It is working fine. We are able to mount > the SD cards that are formatted on Windows systems, but we unable mount > the cards that are formatted using the DIGITAL CAMERA. > > We have found one thing that the Windows and Digital Camera both are > formatting the SD cards in FAT12 only. But why we are not able to mount > the SD cards on Linux Box that are formatted using the Digital Camera. Probably because the camera and linux disagree about the geometry in CHS (cylinder, head, sector) of the flash device. Each partition table entry contains the start and end CHS of that partition. However, since a flash device (and also modern hard drives) doesn't have a meaningful geometry value, the same information is also encoded in logical sectors (start and size of the partition). If the logical information is zero, the kernel falls back onto the CHS information in the partition table and has to assume a certain geometry. If that assumption differs from the assumption of the camera, the partition boundaries will be wrong and you will not be able to mount the partition directly. However, you can figure out the start of the partition by hand, and use a loop device to get at the correct offset. Erik -- Erik Mouw J.A.K.Mouw@xxxxxxxxxxxxxx mouw@xxxxxxxxxxxx
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