A file system is a set of rules and methods that an operating system uses to store, organize, and access files on a storage device, such as a hard drive or solid-state drive. It is responsible for managing the data on the storage device and providing a way for applications to access the data.
For example, the Windows operating system uses the NTFS (New Technology File System) as its default file system. NTFS organizes data into folders and files, and provides features such as encryption, compression, quotas, and auditing. It also provides security features such as access control lists and file permissions.