Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!apple!mips!prls!pyramid!athertn!paul
From: paul@athertn.Atherton.COM (Paul Sander)
Newsgroups: comp.sys.apple
Subject: 35 track floppies (was BASIC.SYSTEM v1.3 Bug)
Summary: Please continue supporting 35 track floppies
Message-ID: <12994@athertn.Atherton.COM>
Date: 26 Sep 89 18:09:44 GMT
References: <890921211121.002635@DOCKMASTER.ARPA> <7834@microsoft.UUCP>
Organization: Atherton Technology, Sunnyvale, CA
Lines: 39

In article <7834@microsoft.UUCP>, brianw@microsoft.UUCP (Brian Willoughby) writes:
[stuff about a bug in BASIC.SYSTEM v1.3 omitted]
> One caveat, I do make it a habit of modifying each version of ProDOS I
> get so that it will access 40 track 5.25 disks.  But I always keep the
> original, unmodified ProDOS around in case bugs show up.  As I mentioned
> above, the errors were indepandant of the ProDOS version, but went away
> when BASIC.SYSTEM v1.2 was used.  BTW, why don't you Apple II ProDOS
> developers just support 40 track 5.25 drives in the standard release
> ProDOS?

Probably because there are still lots of 35 track 5.25" floppy drives out
there.  Many of them are even DISK ][s!

>          That is the only occasion that even tempts me to delve into the
> dark expanses of ProDOS machine code.  (DOS 3.3 had many factors which
> demanded modification!)

What does DOS 3.3 have to do with it?  This is a hardware limitation for some
drives and a media compatibility problem in general.

As I understand it (it's been a while, so this might have changed), 35 tracks
were defined as the standard size for 5.25" floppies, though some manufacturers
discovered that stretching things to 40 tracks worked okay.  This was before
77 track 5.25" floppies came out, but they never really caught on anywhere but
AT class IBM machines and clones (and maybe on Commodore machines).

A better solution would be to write installable drivers for 40-track floppies,
and distribute software on 35-track floppies.

> Brian Willoughby
> UUCP:           ...!{tikal, sun, uunet, elwood}!microsoft!brianw
> InterNet:       microsoft!brianw@uunet.UU.NET
>   or:           microsoft!brianw@Sun.COM
> Bitnet          brianw@microsoft.UUCP

-- 
Paul Sander        (408) 734-9822  | If you must describe both quantity and
paul@Atherton.COM                  | quality of someone else's code, try
{decwrl,pyramid,sun}!athertn!paul  | "awful lot."  -- independent discovery