File System
A file system is the method an operating system uses to organise, name, store and find files on a storage device such as a hard disk, SSD or USB drive. It keeps track of which blocks of the disk belong to which file, arranges files into folders (directories) and records details such as size, dates and permissions.
Common file systems include NTFS (Windows), APFS (macOS), ext4 (Linux), and FAT32 and exFAT, which work on almost every device and are used for USB drives and memory cards. FAT32 cannot store a single file larger than 4 GB, which is why exFAT is used for large files.