|-----------------------------------------------+------------------------------|
| Entire Secondary-Slave IDE hard disk or | /dev/hdd |
| CD-ROM | |
|-----------------------------------------------+------------------------------|
| First SCSI disk | /dev/sda |
|-----------------------------------------------+------------------------------|
| Second and remaining SCSI disks | /dev/sdb and so forth |
|-----------------------------------------------+------------------------------|
| First serial port (COM1 in other OSs) | /dev/ttyS0 |
|-----------------------------------------------+------------------------------|
| Second, third, etc. serial ports | /dev/ttyS1, /dev/ttyS2, etc. |
|-----------------------------------------------+------------------------------|
| SCSI tape units (automatic rewind) | /dev/st0, /dev/st1, etc. |
|-----------------------------------------------+------------------------------|
| SCSI tape units (no automatic rewind) | /dev/nst0, /dev/nst1, etc. |
|-----------------------------------------------+------------------------------|
| SCSI CD-ROMs | /dev/scd0, /dev/scd1, etc. |
+------------------------------------------------------------------------------+

The partitions on each disk are represented by appending a number to the
disk name. For example, the names hda1 and hda2 represent the first and
second partitions of the first IDE disk drive in your system. Linux
represents the primary partitions with the drive name plus the numbers 1
through 4. For example, the first primary partition on the first IDE drive
is /dev/hda1. The logical partitions are numbered starting at 5, so the
first logical partition on that same drive is /dev/hda5. Remember that the
extended partition - that is, the primary partition holding the logical
partitions - is not usable by itself. This applies to SCSI drives as well
as IDE drives.