Unix filesystem: Difference between revisions

Revision as of 14:34, 20 December 2021

Revision as of 14:35, 20 December 2021

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==Principles==

The filesystem appears as one [[rooted tree]] of directories.<ref name="Ritchie"/> Instead of addressing separate volumes such as [[Disk partitioning|disk partitions]], removable media, and [[network share]]s as separate trees (as done in [[DOS]] and [[Microsoft Windows|Windows]]): each ''drive'' has a drive letter that denotes the root of its file system tree), such volumes can be ''[[mount (Unix)|mounted]]'' on a directory, causing the volume's file system tree to appear as that directory in the larger tree.<ref name="Ritchie"/> The root of the entire tree is denoted <code>/</code>.

In the original [[Research Unix|Bell Labs Unix]], a two-disk setup was customary, where the first disk contained startup programs, while the second contained users' files and programs. This second disk was mounted at the empty directory named <code>usr</code> on the first disk, causing the two disks to appear as one filesystem, with the second disk’s contents viewable at <code>/usr</code>.