B.4. Device Names in Linux
Linux disks and partition names may be different from other operating
systems. You need to know the names that Linux uses when you create
and mount partitions. Here's the basic naming scheme:
The first floppy drive is named
The second floppy drive is named
The first SCSI disk (SCSI ID address-wise) is named
The second SCSI disk (address-wise) is named
/dev/sdb, and so on.
The first SCSI CD-ROM is named
The master disk on IDE primary controller is named
The slave disk on IDE primary controller is named
The master and slave disks of the secondary controller can be called
respectively. Newer IDE controllers can actually have two channels,
effectively acting like two controllers.
The first XT disk is named
The second XT disk is named
The partitions on each disk are represented by appending a decimal
number to the disk name:
sda2 represent the first and
second partitions of the first SCSI disk drive in your system.
Here is a real-life example. Let's assume you have a system with 2
SCSI disks, one at SCSI address 2 and the other at SCSI address 4.
The first disk (at address 2) is then named
and the second
sdb. If the
sda drive has 3 partitions on it, these will be
sda3. The same applies to the
sdb disk and its partitions.
Note that if you have two SCSI host bus adapters (i.e., controllers),
the order of the drives can get confusing. The best solution in this
case is to watch the boot messages, assuming you know the drive models
Linux represents the primary partitions as 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
/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 disks as
well as IDE disks.