the whole disk surface of the hard disk is divided into several tracks, and each track is divided into several sectors, which is divided when it is low. The latter concept is about the file system. The file directory indicates how many files or subdirectories there are in a directory. The file allocation table indicates which block on the disk belongs to which file, and the files store information specifically. The structure of the file system is on the disk, not on the disk chip. For details, please refer to books on file system or operating system.