About Device Channl

I have Two CDROM Device,and use ATAPI Command
find the device\'s channel number

Device 1 in IDE1 Master Channel Number = 1:0
Device 2 in IDE1 Selver Channel Number = 1:1

but i don\'t know who to find the device \'s Disk Number

Sample:
          Device 1 = 1:0 E:
          Device 2 = 1:1 F:

要如何找到相