Next: 2.2.3 Linux partition requirements Up: 2.2 Preparing to Install Previous: 2.2.1 Installation overview

## 2.2.2 Repartitioning concepts

In general, hard drives are divided into 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 repartitioning.

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

On the first sector of the disk is a master boot record along with a 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: primary, extended, and 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.

Next: 2.2.3 Linux partition requirements Up: 2.2 Preparing to Install Previous: 2.2.1 Installation overview