Macintosh File System
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Macintosh File System (MFS) is a
format (or disk
) created by
for storing
on 400K
. MFS was introduced with the original
computer in January 1984.
MFS is notable both for introducing
to allow storage of structured data, and for storing
needed to support the
of
. MFS allows file names to be up to 255
in length, although
does not allow users to create names longer than 63 characters (31 characters in later versions). MFS is called a
because it does not support a hierarchy of
.
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 in
windows, but not in the open and save
. 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. While this is small by today's standards, at the time it seemed very expansive when compared to the
's 400 KB floppy drive.
Apple introduced
as a replacement for MFS in September 1985. In
, Apple removed support for writing to MFS volumes,
and in
support for MFS volumes was removed altogether. Although
has no built-in support for MFS, an example VFS plug-in from Apple called MFSLives provides read-only access to MFS volumes.
See also
References
Bibliography
- Apple Computer, Inc. (1985). Inside Macintosh Volume II. New York: Addison-Wesley. ISBN 0-201-17732-3.
External links
- Apple Tech Article 9502 - MFS volume support in Mac OS 7.x
- MacTech Volume 1, Issue 5: Disks - organization of the standard Macintosh disk (April 1985)
- Resurrecting MFS Macintosh Floppies
- Fred's Follies - HFS used in Macs with 128K ROMs different from MFS used in Macs with 64K ROMs
- Q&A: Mac Plus - limitation due to MFS on an external 400K floppy drive disk
- MFSLives - VFS read-only plug-in for MFS in macOS