Path: utzoo!attcan!uunet!munnari.oz.au!bruce!monu1!vaxc!phs172m
From: phs172m@vaxc.cc.monash.edu.au (Stephen Harker)
Newsgroups: comp.sys.apple2
Subject: Re: AE 1.6 MB 3.5" drive
Message-ID: <77740.2763bf3e@vaxc.cc.monash.edu.au>
Date: 10 Dec 90 06:00:46 GMT
References: <248@generic.UUCP>
Organization: Computer Centre, Monash University, Australia
Lines: 37

In article <248@generic.UUCP>, taob@pnet91.cts.com (Brian Tao) writes:
> From johnmac@fawlty.towers.oz (John MacLean):
> 
>> Use of the 1.44 Meg format would mean that AE would have to provide a
>> GS/OS device driver that would provide access to IBM/Mac disks with this
>> format. You then have the potential to add FSTs for these formats, and
>> to write simple conversion programs if Apple never produces the goods.
>> These advantages far outweigh an extra 156K per disk. It may be nice to
>> have a 1.6meg driver, but this needs to be a secondary consideration. 
> 
>     I agree.  No one (and I mean NO ONE) uses a 1.6-meg floppy format.  The
> 800K standard isn't as bad since the Mac also reads/writes 800K floppies. 
> When you think high-density, you automatically think 1.44-meg floppies.  It
> would be so much "cleaner" if AE just gave us a standard 1.44-meg drive.
> 
>     It looks like the 2.88-meg floppy will become the standard in a couple of
> years (or less).  The NeXT already uses it, and some laptops will be using it
> in the near future.
> 
The real difficulty, as I understand it, is that to get the so called 1.44Meg
format (1.4Meg actually) you need the SWIM chip rather than the IWM on the GS
motherboard.  This is why all the later Mac's went to the SWIM, and why it was
included in the Mac SE upgrade.  Without the SWIM you can't write the
appropriate disk format (MFM I think) needed.

This is also seen in the necessity to connect the Apple 3.5 drive directly to a 
PC Transporter card in order to read/write IBM format 720K 3.5 disks.  The PC
transporter incorporates a standard PC MFM drive controller.

Of course this raises the question of when/whether Apple will incorporate the
SWIM on the GS motherboard, or offer an upgrade.  The answer, the last I heard
is no.  This is another unfortunate indication of Apple's support for the II
line.

-- 
Stephen Harker				phs172m@vaxc.cc.monash.edu.au
Monash University