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Chapter 5. Managing Storage

holding the files comprising the operating system will not be affected even if the partition holding the

users' files becomes full. The operating system will still have free space for its own use.

Although it is somewhat simplistic, you can think of partitions as being similar to individual disk

drives. In fact, some operating systems actually refer to partitions as "drives". However, this viewpoint

is not entirely accurate; therefore, it is important that we look at partitions more closely.

5.5.1.1. Partition Attributes

Partitions are defined by the following attributes:

Partition geometry

Partition type

Partition type field

These attributes are explored in more detail in the following sections.

5.5.1.1.1. Geometry

A partition's geometry refers to its physical placement on a disk drive. The geometry can be specified

in terms of starting and ending cylinders, heads, and sectors, although most often partitions start and

end on cylinder boundaries. A partition's size is then defined as the amount of storage between the

starting and ending cylinders.

5.5.1.1.2. Partition Type

The partition type refers to the partition's relationship with the other partitions on the disk drive. There

are three different partition types:

Primary partitions

Extended partitions

Logical partitions

The following sections describe each partition type.

5.5.1.1.2.1. Primary Partitions

Primary partitions are partitions that take up one of the four primary partition slots in the disk drive's

partition table.

5.5.1.1.2.2. Extended Partitions

Extended partitions were developed in response to the need for more than four partitions per disk drive.

An extended partition can itself contain multiple partitions, greatly extending the number of partitions

possible on a single drive. The introduction of extended partitions was driven by the ever increasing

capacities of new disk drives.