Editing File system (section)

== Architecture ==

A local file system's [[software architecture|architecture]] can be described as [[Abstraction layer|layers of abstraction]] even though a particular file system design may not actually separate the concepts.<ref name="JHU">{{cite web|last1=Amir|first1=Yair|title=Operating Systems 600.418 The File System|url=http://www.cs.jhu.edu/~yairamir/cs418/os7/sld001.htm|website=Department of Computer Science Johns Hopkins University|access-date=July 31, 2016}}</ref>

The ''logical file system'' layer provides relatively high-level access via an [[application programming interface]] (API) for file operations including open, close, read and write {{endash}} delegating operations to lower layers. This layer manages open file table entries and per-process file descriptors.<ref name="IBMKC">{{cite web|last1=IBM Corporation|title=Component Structure of the Logical File System|url=https://www.ibm.com/docs/en/aix/7.3?topic=overview-component-structure-logical-file-system|website=IBM Knowledge Center|access-date=April 24, 2024}}</ref> It provides file access, directory operations, security and protection.<ref name=JHU />

The ''virtual file system'', an optional layer, supports multiple concurrent instances of physical file systems, each of which is called a file system implementation.<ref name=IBMKC />

The ''physical file system'' layer provides relatively low-level access to a storage device (e.g. disk). It reads and writes [[Block (data storage)|data blocks]], provides [[Data buffer|buffer]]ing and other [[memory management]] and controls placement of blocks in specific locations on the storage medium. This layer uses [[device driver]]s or [[channel I/O]] to drive the storage device.<ref name=JHU />