% Linux Installation and Getting Started    -*- TeX -*-
% concepts.tex
% Copyright (c) 1992-1994 by Matt Welsh <mdw@sunsite.unc.edu>
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\subsection{Repartitioning concepts}

\index{installation!repartitioning}
\index{repartitioning!concepts}
\index{partitions}
In general, hard drives are divided into {\em partitions}, where a single
partition is devoted to a single operating system. For example, on one
hard drive, you may have several separate partitions---one devoted to,
say, MS-DOS, another to OS/2, and another to Linux.

If you already have other software installed on your system, you may need
to resize those partitions in order to free up space for Linux. You will
then create one or more Linux partitions on the resulting free space for
storing the Linux software and swap space. We call this process
{\em repartitioning}.

Many MS-DOS systems utilize a single partition inhabiting the entire 
drive. To MS-DOS, this partition is known as {\tt C:}. If you have more than 
one partition, MS-DOS names them {\tt D:}, {\tt E:}, and so on. 
In a way, each partition acts like a separate hard drive.

\index{master boot record}
\index{partition table}
On the first sector of the disk is a {\bf master boot record} along with 
a {\bf partition table}. The boot record (as the name implies) is used to 
boot the system. The partition table contains information about the locations 
and sizes of your partitions. 

There are three kinds of partitions: {\bf primary}, {\bf extended}, and
{\bf logical}. Of these, primary partitions are used most often.
However, because of a limit in the size of the partition table, you can
only have four primary partitions on any given drive.

The way around this four-partition limit is to use an extended partition.
An extended partition doesn't hold any data by itself; instead, it acts
as a ``container'' for logical partitions. Therefore, you could create one 
extended partition, covering the entire drive, and within it create many
logical partitions. However, you may have only one extended partition per
drive.

