On my computer I see the following drives in BIOS:
- IDE channel 0 Master (none)
- IDE channel 0 Slave (none)
- IDE channel 2 Master (my HDD)
- IDE channel 2 Slave (my DVD drive)
What is the meaning of these numbers?
Each IDE channel is a independent data channel hooked into the south bridge. With IDE, this supports two disks (master and slave) which share the bandwidth on that channel.
Physically each 'channel' connects to a single ribbon cable, which connects to those two drives, with their 'role' set explicitly by jumper setting to master and slave, or automatically by setting those jumpers to cable select.
Practically this means that your HDD and DVD drive are sharing bandwidth, and are on the same channel, and you might want to move it.
I'd note IDE is currently referred to as PATA, and is considered obsolete. Modern drives are sata and have a drive per channel.