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An Introduction to Disk Partitions
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This appendix is not necessarily applicable to architectures other than AMD64 and Intel{nbsp}64. However, the general concepts mentioned here may apply.
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This section discusses basic disk concepts, disk repartitioning strategies, the partition naming scheme used by Linux systems, and related topics.
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If you are comfortable with disk partitions, you can skip ahead to xref:sect-disk-partitions-making-room[Strategies for Disk Repartitioning] for more information on the process of freeing up disk space to prepare for a {PRODUCT} installation.
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Hard Disk Basic Concepts
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Hard disks perform a very simple function - they store data and reliably retrieve it on command.
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When discussing issues such as disk partitioning, it is important to have a understanding of the underlying hardware; however, since the theory is very complicated and expansive, only the basic concepts will be explained here. This appendix uses a set of simplified diagrams of a disk drive to help explain what is the process and theory behind partitions.
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xref:figu-partitions-unused-drive[An Unused Disk Drive], shows a brand-new, unused disk drive.
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An Unused Disk Drive
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Image of an unused disk drive.
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partitions/unused-drive.png
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File Systems
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To store data on a disk drive, it is necessary to _format_ the disk drive first. Formatting (usually known as "making a _file system_pass:attributes[{blank}]") writes information to the drive, creating order out of the empty space in an unformatted drive.
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Disk Drive with a File System
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Image of a formatted disk drive.
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partitions/formatted-drive.png
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As xref:figu-partitions-formatted-drive[Disk Drive with a File System], implies, the order imposed by a file system involves some trade-offs:
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A small percentage of the driver's available space is used to store file system-related data and can be considered as overhead.
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A file system splits the remaining space into small, consistently-sized segments. For Linux, these segments are known as _blocks_ footnote:[Blocks really *are* consistently sized, unlike our illustrations. Keep in mind, also, that an average disk drive contains thousands of blocks. The picture is simplified for the purposes of this discussion.].
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Note that there is no single, universal file system. As xref:figu-partitions-different-file-system[Disk Drive with a Different File System], shows, a disk drive may have one of many different file systems written on it. 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. However, {PRODUCT} supports a wide variety of file systems (including many commonly used by other operating systems such as Microsoft Windows), making data interchange between different file systems easy.
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