There are three things you need to know before you mount a partition:
a) The hard disk place, this is as follows:
IDE
Primary controller, Master position: HDA
Primary controller, Slave position: HDB
Senondary controller, Master position: HDC
Secondary Contrller, Slave position: HDD
[...]
SCSI and SATA
First controller, first position: SDA
First controller, second position: SDB
[..]
b) The partition position, this is attached next to the hard drive and is as follows:
Primary partitions:
First: 1, Second: 2, Third: 3, Fourth: 4
Logical partitions:
First: 5, Second 6, Third 7, [...]
I.e. the first logical partition of an IDE hard disk as a primary master would be "hda5".
You can check the partitions of a hard drive and their position via the fdisk or cfdisk commands.
c) The partition type. A list of all partition types is included in the man page of mount ("man mount"). In many cases it is not necessary to define the partition type, but not always. You can define it with the "-t" switch of mount, i.e. to mount a NTFS filesystem that lays on the first logical partition of an IDE hard disk as a primary master, you could type:
"mount -t ntfs /dev/hda5 /mnt/tmp" 
