For those who are used to dos or windows systems, drives and partitions are always same in number. Each partition is assigned a letter for different identity, then we can set files and profiles on this partition, and the file map is very clear to see.
Now let's talk about how the drive is identified under read hat Linux system.
IDE hard drive will be showed as hdx~ of which, hd indicates the type of device, here refers to hard disk. X stands for the drive letter, a is the primary disk, b is the subordinate disk, c is assistant primary disk and d is assistant subordinate disk. ~ stands for partitions. The first four partitions are marked with numbers from 1 to 4. They are primary partitions and extended partitions. The rest of the partitions from partition 5 are all logical partitions. For instance, hda3 stands for the third primary or extended partitions on the first IDE hard disk. Hdb2 stands for the second primary partition or extended partition on the second IDE hard disk. SCSI hard disk is marked as sdx~, in which sd stands for the type of devices, SCSI. The rest is the same with that of IDE hard disks.
We can see now that red hat Linux is different from other Operating Systems in terms of partitions. Its partitions have only two formats: ext2 and ext3. Ext2 is used to store system files and swap works as an exchange partition of red hat Linux. Now we know that red hat Linux needs at least two partitions, Linux native and Linux swap. Moreover, red hat Linux cannot be installed on DOS/Windows partitions. Commonly, we would install red hat Linux on one or several Linux native partitions. But each partition should be set with a mount point to tell the system which directory to use when Linux boots. It is not necessary for swap partitions to set mount point.