Zlatin,

>Example:
>three hard drives:
>(IDE0 Master)1st: Partition1 - letter C: ; Partiotion2 - letter E:; Partiotion3 - letter F:
>(IDE1 Master)2nd: Partition1 - letter D: ; Partition2 - letter G:
>(IDE0 Slave) 3rd: Partition1 - letter H:
>
>I ask my program: which is the hard drive number of logical drive letter E:
>It should say 1

I thought that the serial number might give you an indication about the physical disk. Using your example, drives C,E and F would have the same serial number, drives D and G another and drive H yet another serial number. When I tested this, I got different serial numbers for my HD, Jaz, CD-ROM, etc. But I failed to notice that two different partitions on the same HD returned different serial numbers.