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I'm trying to load a file from a FAT12 filesystem:

LBA = (Cluster - 2) * SectorsPerCluster

Why : Cluster - 2

Thanks.

If i got you right, and you are talking about the data area of the FAT, this happens because the first two entries on the FAT table are reserved. So the first sector of data is actually the third sector on the FAT.

Hope this helps.

thanks, it's helpful,, but what is the first logical cluster and what does it point to?

renovatio wrote:thanks, it's helpful,, but what is the first logical cluster and what does it point to?

that depends, first logical sector of where?
If its from the disk than it points to the first physical sector of the disk.
If its the first logical sector of the data area it points well... to the start of the data on the fat, which probably is not the first logical sector.

If this maybe of some help, you can take a look at my bootloader to see if it makes things clearer for you
http://code.google.com/p/the-kos/source ... t/boot.asm

Cheers

many thanks for your reply...