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| Developer(s) | Apple Computer, Inc. |
|---|---|
| Full name | Macintosh File System |
| Introduced | January 24, 1984; 42 years ago (1984-01-24) withSystem 1 |
| Succeeded by | HFS |
| Partition IDs | Apple_MFS (Apple Partition Map) |
| Structures | |
| Directory contents | Table |
| File allocation | Linked list |
| Bad blocks | No |
| Limits | |
| Max volume size | 20MiB |
| Max file size | 20MiB |
| Maxno. of files | 4094 |
| Max filename length | 255 characters |
| Allowed filename characters | Any printable character except “:” |
| Features | |
| Dates recorded | Creation, modification |
| Date range | January 1, 1904 – February 6, 2040 |
| Date resolution | 1s |
| Forks | Only 2 (data andresource) |
| Attributes | version, locked, type, creator, Finder window, location in Finder window, Finder flags |
| File system permissions | No |
| Transparent compression | No |
| Transparent encryption | No |
| Other | |
| Supported operating systems | System 1 —Mac OS 7.6, Mac OS 7.6.1 (read-only) |
Macintosh File System (MFS) is avolume format (or diskfile system) created byApple Computer for storingfiles on 400Kfloppy disks. MFS was introduced with the originalApple Macintosh computer in January 1984.
MFS is notable both for introducingresource forks to allow storage of structured data, and for storingmetadata needed to support thegraphical user interface of theclassic Mac OS. MFS allows file names to be up to 255characters in length,[1] althoughFinder does not allow users to create names longer than 63 characters (31 characters in later versions). MFS is called aflat file system because it does not support a hierarchy ofdirectories.
Folders exist as a concept on the original MFS-based Macintosh, but work completely differently from the way they do on modern systems. They are visible inFinder windows, but not in the open and savedialog boxes.[2] There is always one empty folder on the volume, and if it is altered in any way (such as by adding or renaming files), a new Empty Folder appears, thus providing a way to create new folders. MFS stores all of the file and directory listing information in a single file. The Finder creates the illusion of folders, by storing all files as pairs of directory handles and file handles. To display the contents of a particular folder, MFS scans the directory for all files in that handle. There is no need to find a separate file containing the directory listing.
The Macintosh File System does not support volumes over 20 MB in size, or about 1,400 files.[citation needed] While this is small by today's standards, at the time it seemed very expansive when compared to theMacintosh's 400 KB floppy drive.
Apple introducedHierarchical File System as a replacement for MFS in September 1985. InMac OS 7.6.1, Apple removed support for writing to MFS volumes “as such writes often resulted in errors or system hangs”,[3] and inMac OS 8.0 support for MFS volumes was removed altogether. AlthoughmacOS (formerly Mac OS X) has no built-in support for MFS, an example VFS plug-in from Apple called MFSLives provides read-only access to MFS volumes.[4]