On the jumpers on the drives you should see M/S/CS (master/slave/cable select). This will mean that the devices negotiate their IDE master/slave status between themselves automatically. You'll need to set all the channels to "auto" in the BIOS as well.
Note that for CS to work:
- All drives must support it, and have it selected
- The motherboard must support it
- The IDE cable must support it
At the first sign of trouble (and I usually don't even wait for that ) I always scrap CS and specify M/S as desired.
Also note that some drives differentiate between "master - only drive" and "master - slave present", so check those jumpers.
Symptoms of getting it wrong are not usually as simple as "it doesn't work". Sometimes it'll half-boot, sometimes the drives types (eg manufacturer details) will be shown as garbage in the BIOS screens, sometimes it'll work - and all those symptoms can apply to the same PC with the same hardware.
This is very much a hardware dependant problem - you'll find examples where you have a controller and hard drive set where one can be set to master and the other set to cable select, and never have any problems with it - however that may be a rarer coiincidence then anything else.
Garbage on bios can also be caused by other problems, especially power supply problems, where the system asks the drive what it is, and there is a surge or a drop in power, the return value can get munged - I've had that happen before when drawing a ermm little too much at once...
JT