User's Manual

Section E.1:Hard Disk Basic Concepts 117

This letter indicates which device the partition is on. For example, /dev/hda (the first IDE

hard disk) or /dev/sdb (the second SCSI disk).

The final number denotes the partition. The first four (primary or extended) partitions are num-

bered 1 through 4. Logical partitions start at 5. So, for example, /dev/hda3 is the third

primary or extended partition on the first IDE hard disk, and /dev/sdb6 is the second logical

partition on the second SCSI hard disk.

Note

There is no part of this naming convention that is based on partition type;

unlike DOS/Windows, all partitions can be identified under Red Hat Linux.

Of course, this does not mean that Red Hat Linux can access data on every

type of partition, but in many cases it is possible to access data on a partition

dedicated to another operating system.

Keep this information in mind; it will make things easier to understand when you are setting up the

partitions Red Hat Linux requires.

E.1.6 Disk Partitions and Other Operating Systems

If your Red Hat Linux partitions will be sharing a hard disk with partitions used by other operating sys-

tems, most of the time you will have no problems. However, there are certain combinations of Linux

and other operating systems that require extra care. Information on creating disk partitions compatible

with other operating systems is available in several HOWTOs and Mini-HOWTOs, available on the

Red Hat Linux Documentation CD in the HOWTO and HOWTO/mini directories. In particular, the

Mini-HOWTOs whose names start with Linux+ are quite helpful.

E.1.7 Disk Partitions and Mount Points

One area that many people new to Linux find confusing is the matter of how partitions are used and

accessed by the Linux operating system. In DOS/Windows, it is relatively simple: Each partition gets

a "drive letter." You then use the correct drive letter to refer to files and directories on its corresponding

partition.

This is entirely different from how Linux deals with partitions and, for that matter, with disk storage

in general. The main difference is that each partition is used to form part of the storage necessary to

support a single set of files and directories. This is done by associating a partition with a directory

through a process known as mounting. Mounting a partition makes its storage available starting at

the specified directory (known as a mount point).