108、Most operating systems provide a file system, as a file system is an integral part of any modern operating system.Early microcomputer operating systems’ only real task was file management - a fact reflected in their names ( ).Some early operating systems had a separate component for handling file systems which was called a disk operating system.On some microcomputers, the disk operating system was loaded separately from the rest of the operating system.On early operating systems, there was usually support for only one, native, unnamed file system; for example, CP/M supports only its own file system, which might be called “CP/M file system” if needed, but which didn＇t bear any official name at all. Because of this, there needs to be an interface provided by the operating system software between the user and the file system.This interface can be textual ( ) or graphical ( ).If graphical, the metaphor of the folder, containing documents, other files, and nested folders is often used ( ). In a flat file system, there are no subdirectories-everything is stored at the same ( ) level on the media, be it a hard disk, floppy disk, etc.While simple, this system rapidly becomes inefficient as the number of files grows, and makes it difficult for users to organize data into related groups. Like many small systems before it, the original Apple Macintosh featured a flat file system, called Macintosh File System.Its version of Mac OS was unusual in that the file management software ( ) created the illusion of a partially hierarchical filing system on top of MFS.This structure meant that every file on a disk had to have a unique name, even if it appeared to be in a separate folder.MFS was quickly replaced with Hierarchical File System, which supported real directories.(2)、The types of interface between user and file system include___.