The second optional layer is the virtual file system. This layer provides 'file access, directory operations, security and protection'. The logical file system 'manage open file table entries and per-process file descriptors'.

It provides the application program interface (API) for file operations - OPEN, CLOSE, READ, etc., and passes the requested operation to the layer below it for processing. The logical file system is responsible for interaction with the user application. Sometimes the layers are explicitly separated, and sometimes the functions are combined. Architecture Ī file system consists of two or three layers. By 1961, the term was being applied to computerized filing alongside the original meaning. It is responsible for arranging storage space reliability, efficiency, and tuning with regard to the physical storage medium are important design considerations.īefore the advent of computers the term file system was used to describe a method of storing and retrieving paper documents. The file system manages access to both the content of files and the metadata about those files.

Some file systems are 'virtual', meaning that the supplied 'files' (called virtual files) are computed on request (such as procfs and sysfs) or are merely a mapping into a different file system used as a backing store. Some file systems are used on local data storage devices others provide file access via a network protocol (for example, NFS, SMB, or 9P clients). In some cases, such as with tmpfs, the computer's main memory ( random-access memory, RAM) is used to create a temporary file system for short-term use. Other kinds of media that are used include SSDs, magnetic tapes, and optical discs.

As of 2019, hard disk drives have been key storage devices and are projected to remain so for the foreseeable future. For example, the ISO 9660 and UDF file systems are designed specifically for optical discs.įile systems can be used on many types of storage devices using various media. Some file systems have been designed to be used for specific applications. There are many kinds of file systems, each with unique structure and logic, properties of speed, flexibility, security, size and more. The structure and logic rules used to manage the groups of data and their names is called a 'file system.' Taking its name from the way a paper-based data management system is named, each group of data is called a ' file'. By separating the data into pieces and giving each piece a name, the data are easily isolated and identified. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. In computing, a file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved.

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