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Appendix E. An Introduction to Disk Partitions

Figure E 2. Disk Drive with a File System

As Figure E 2, implies, the order imposed by a file system involves some trade offs:

A small percentage of the drive's available space is used to store file system related data and can be

considered as overhead.

A file system splits the remaining space into small, consistently sized segments. For Linux, these

segments are known as blocks.

1

Given that file systems make things like directories and files possible, these tradeoffs are usually seen

as a small price to pay.

It is also worth noting that there is no single, universal file system. As Figure E 3, shows, a disk

drive may have one of many different file systems written on it. As you might guess, different file

systems tend to be incompatible; that is, an operating system that supports one file system (or a

handful of related file system types) may not support another. This last statement is not a hard and 

fast rule, however. For example, Red Hat Linux supports a wide variety of file systems (including

many commonly used by other operating systems), making data interchange between different file

systems easy.

Figure E 3. Disk Drive with a Different File System

Of course, writing a file system to disk is only the beginning. The goal of this process is to actually

store and retrieve data. Let us take a look at our drive after some files have been written to it.

1. Blocks really are consistently sized, unlike our illustrations. Keep in mind, also, that an average disk drive

contains thousands of blocks. But for the purposes of this discussion, please ignore these minor discrepancies.