9 Feb
2007
9 Feb
'07
5:33 a.m.
Message: 23
Date: Thu, 8 Feb 2007 12:27:00 -0800 (PST)
From: Fred Cisin <cisin at xenosoft.com>
Subject: Re: Copying a Mac Disk with a Single Drive
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Message-ID: <20070208122504.I35814 at shell.lmi.net>
Content-Type: TEXT/PLAIN; charset=US-ASCII
On Wed, 7 Feb 2007, Scott Quinn wrote:
Not sure about dimensions- the 800/400k drives I think share common
dimensions with the PC-esque 720k drives, and the 1.4 SuperDrive is
known to be the same dimension as the 1.44 MB PC mechanism.
It was big issue around the time System 7 came out- if you put a 800k
diskette in a System 7 machine with a SuperDrive the desktop file would
be rewritten unless the disk was locked. If you then put the disk in a
800k System 6 drive it would indicate it as corrupt (you could run it
through Disk First Aid to get it back) because of the head sizes
(similar to the problem with 5.25" DD floppies in the PC AT)
with an external 400 or 800k floppy. The
SuperDrive (original
SuperDrive, not the "new" CD/DVD one) [present on all Macs since the
IIx, many IIs and some SEs (SE FDHD)] has the smaller head size and
your older machine won't read it properly. WRT the swapping- can't
There is a completely different recording method (MFM v Mac GCR).
What are the dimensions of the different size heads?