Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!hp4nl!duteca!thomas
From: thomas@duteca (Thomas Okken)
Newsgroups: comp.sys.mac.misc
Subject: Using 400K disks w/System 7 (was: Re: THE most subtle change in System 7)
Message-ID: <1337@duteca.UUCP>
Date: 30 May 91 01:19:28 GMT
References: <1991May29.040751.5773@rs6000.cmp.ilstu.edu>
Organization: Delft University of Technology, Netherlands
Lines: 30

From article <1991May29.040751.5773@rs6000.cmp.ilstu.edu>, by ejbehr@rs6000.cmp.ilstu.edu (Eric Behr):
>>In comp.sys.mac.misc, chai@hawk.cs.ukans.edu (Ian Chai) writes:
>>
>>    In article <16556@helios.TAMU.EDU> mkh6317@zeus.tamu.edu writes:
>>    >Did you notice that the little dot that used to be to the far
>>    >left, inbetween the thin double lines at the top of the finder
>>    >windows is GONE!  Now how are we supposed to differentiate between
>>    >a MFS and a HFS disk? Huh? ;-).
>>
>>    You don't. MFS is dead. 400k disks aren't supported anymore...
>>    (Yes, I even tested this out... weird errors result...)
>>    >
> What's the story here? The "late breaking news" on the Compatibility
> Checker disk claims that MFS disks can be read, just not modified. I
> may need to do it, so I'm curious: what "weird errors" have you seen?

In fact, you can still use 400K disks IF they have an HFS directory. To get
this, hold down Option, select Erase Disk from the Special menu, keep the
Option key down until the formatting is completely finished, that is, until
the alert box disappears.
You then have an HFS disk, with fully functional folders (the kind that
actually shows up in the Standard File dialogs). And this disk can be read
by *any* Mac, including the 128K (if running System 3.2 or higher).
Note that this trick works with all System versions from 3.2. Yes, even with
System 7.0: I just tried it.
So, if you need to write to a 400K disk: copy everything from the disk to
your HD, reformat the floppy using the above procedure, copy your stuff back,
et voila: everything works just fine.

 - Thomas (thomas@duteca.et.tudelft.nl)