The Macintosh File System, or MFS, is the original Macintosh filesystem created for use on 400K floppy drives. It was created on January 1984, and Discontinued September 1985 with the introduction of the HFS filesystem. Write support was removed in Mac OS version 7.6, and read support was removed in version 8.
The max file and volume size was 256 MiB. There could only be 4094 files, and there were no real folders; all file information was stored in a single file, and then the Mac operating system turned that information into folders of a sort.