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From: rs4u#@ANDREW.CMU.EDU (Richard Siegel)
Newsgroups: comp.sys.mac
Subject: Re: 512K Mac/800K Drive
Message-ID: 
Date: Fri, 12-Dec-86 11:25:07 EST
Article-I.D.: andrew.MS.V3.18.rs4u.80020be1.knox.ibm032.2208.1
Posted: Fri Dec 12 11:25:07 1986
Date-Received: Mon, 15-Dec-86 05:59:37 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: University of California at Berkeley
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[Line-Eater? What Line-Eater? *Chomp* 8-) ]

Organization: Carnegie-Mellon University, Pittsburgh, Pa.
Position: Confused Undergraduate


I've been using a plain-vanilla 512K Macintosh with Apple's 800K disk drive
for a while now; here are some comments and responses:


I have a system disk that has my favorite INIT resources (SortMenu), and the
Hard Disk 20 file on it. I boot with that. In the external drive, I put in an
800K HSF system disk. Depending on what I am doing, it's either my Lightspeed
Pascal development disk, or else it's a disk that has MacWrite, MacDraw, and
full set of fonts and desk accessories, and still plenty of room for
documents. With the 800K disk outboard, I can use the internal drive
(single-sided, of course) as my "Data Disk", where I keep all my documents.

It is possible to format an 800K disk as MFS, but it's not desirable, since
HFS is much nicer. But of course, there are some nonstandard applications
that don't like HFS. So here's how to do it: Prepare a startup disk that has
a System, Finder, and modified Hard Disk 20 file on it. The modified Hard
Disk 20 file is made in the following way: 

	make a copy of the Hard Disk 20 file. 
	open it up with ResEdit.
	You'll notice that in the file there are three 'PTCH' ("Patch")
resources. Remove ALL of them >>EXCEPT<< the one called '.Sony'. (This is the
driver for the double-sided drive). 

Save the file and quit.
Boot with this modified disk.

You've removed that patches that make the system recognize HFS, so when you
format a disk in the 800K drive, it'll be formatted as 800K MFS. Disks
formatted in the single sided drive are 400K MFS. 

Notice that if you boot with this disk the Finder won't recognize HFS
floppies at all ("This is not a Macintosh disk").

As I said, format your doublesided disks as HFS, because it's the better way
to go.

Formatting a 400K disk as HFS is a waste of time, in my opinion... Just hold
down the Option key when you choose "Erase Disk", and hold it down until it's
done, and if you're naming a new disk via the Initialize box, hold down the
Option key when you hit Return or press the OK button. But you have to have
the Hard Disk 20 file loaded at bootup.

You must have the new system software to run with the external 800K drive, if
you haven't got the new ROMs. I think. 8-)

There's nothing wrong with using a 400K disk in an 800K drive. What's a
little riskier is using a 400K disk, formatting it on both sides, and then
using it as an 800K disk. I have done it, but you're playing with fire. Spend
the extra money to get doublesided disks. I learned the hard way, when I
started getting random I/O errors. I copied stuff to a new double-sided disk,
and all my problems went away, and have stayed away.

If you insist on using single-sided disks as double-sided disks, DON'T USE
ANYTHING BUT SONY. Anything else is certain trouble.

Hope this helps....

		--Rich