Red Hat LINUX ES 2.1 -, Руководство по установке

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Appendix D. An Introduction to Disk Partitions 89
y
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).
N
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 Enterprise Linux ES. Of course, this does not mean that
Red Hat Enterprise Linux ES 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 Enterprise Linux ES requires.
D.1.6. Disk Partitions and Other Operating Systems
If your Red Hat Enterprise Linux ES partitions will be sharing a hard disk with partitions used by other
operating systems, most of the time you will have no problems. However, there are certain combina-
tions of Linux and other operating systems that require extra care. Information on creating disk parti-
tions compatible with other operating systems is available in several HOWTOs and Mini-HOWTOs,
available on the Red Hat Enterprise Linux ES Documentation CD in the
HOWTO
and
HOWTO/mini
directories. In particular, the Mini-HOWTOs whose names start with
Linux+
are quite helpful.
D.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 ).
For example, if partition
/dev/hda5
were mounted on
/usr
, that would mean that all
files and directories under
/usr
would physically reside on
/dev/hda5
. So the file
/usr/share/doc/FAQ/txt/Linux-FAQ
would be stored on
/dev/hda5
, while the file
/etc/X11/gdm/Sessions/Gnome
would not.
Continuing our example, it is also possible that one or more directories below
/usr
would be
mount points for other partitions. For instance, a partition (say,
/dev/hda7
) could be mounted on
/usr/local
, meaning that
/usr/local/man/whatis
would then reside on
/dev/hda7
rather
than
/dev/hda5
.