File system

A file system is a way of organizing, storing and naming data on storage media that defines the storage structure (files, directories, metadata), methods of accessing them, and rules of disk space management. It provides a unified interface for the operating system and applications by abstracting the physical features of the storage media (HDD, SSD, network storage).

The main functions of a file system are:

• Organization of data in the form of files and directories (folders) that can be nested within each other, forming a hierarchical structure.
• Managing file names and their attributes (size, creation date, access rights, etc.).
• Defining data storage format and space allocation on the media.
• Provide access to files without the need to know the physical location of data on disk.
• Support additional features such as access delimitation, encryption, versioning, and data recovery.

In modern operating systems, file systems vary in purpose and technical implementation. Traditional hard drives often use NTFS in Windows or ext4 in Linux, while SSDs use optimized solutions like APFS in macOS or F2FS in mobile devices. In distributed environments, CephFS and HDFS are popular, and specialized systems like OverlayFS are created for containers. Standing out are advanced file systems like ZFS and Btrfs, which combine data protection features, snapshots, and built-in encryption.

How a file system works:

A file system doesn't just organize data as files and folders - it completely abstracts the physical features of the media, providing a single interface to work with. At the same time, metadata management, including access rights and timestamps, is implemented differently: in UNIX systems through inode, in others through alternative mechanisms. Modern implementations necessarily support journaling, as in ext4 or NTFS, which protects against data loss in case of failures. Additional features like snapshots in ZFS or transparent compression in Btrfs make file systems a key component for reliable storage in any environment, from personal devices to distributed cloud storage.

Thus, a file system solves a whole range of problems: from basic storage organization to advanced fault tolerance and security features. At the same time, each implementation - be it the time-tested ext4 or the modern CephFS - is optimized for specific usage scenarios and hardware types.