Comment 6 for bug 932321

One more comment:
The cylinders, tracks/cylinder, sectors/track data is something that Windows makes up since the sd-card or thumbdrive is not structured like that, they only report the total size in blocks, where 1 block = 512 bytes.

Since the c, t, s values are integers, Windows must pick c, t and s values so that the formula c * t * s gives a conservative approximation of the disk size, but this is very likely not the correct size.