drive letter assignment with 2 hdd’s

Hi,
I have a 40 gb hdd partitioned c,d,e that I had to use the cylinder limitation jumper to bypass the 32gb limits of the bios. I have it set to master and using the cylinder limitation jumper and the secong 6gb hdd partitioned c,d set as slave. The 2 drives are found and report the size as expected 40gb as 32 and 6gb as 6gb. The question is, why has the 40 gb primary partition been given c and the 6gb primary partition been given d letters rather than c,d,e on the 40gb and e,f on the 6gb. Partition 1 on the 40gb and partition 1 on the 6 are set active.