Date   : Tue, 23 Mar 2010 18:16:32 +0000
From   : afra@... (Phill Harvey-Smith)
Subject: Re-using floppies

Jules Richardson wrote:
> I believe 40-cylinder 3.5" drives did exist, but are extremely rare.

They do indeed exist, and yes they are rare, I've only ever seen 1 in 
about 25 years.....

> 5.25" world further muddied by 77-track drives, 35-track drives, non-Shugart 
> drives (Apple etc.), drives that expect disks with hub rings and drives that 
> don't (most don't care, thankfully), drives that run at funny speeds, drives 
> that are fixed to a specific address etc. :-)

But arn't 35 and 77 track drives just 40 and 80 track drives formatted 
with less tracks (Cirtainly this is true of the Tandy CoCo's drives 
which are 35 track).

Plus there's also hard sectored disks that have not 1 but n+1 holes in 
the hub area, where n=number of sectors. It's fun trying to format one 
of those in a noremal drive......

Then there's flippy disks which have two sync holes so you can flip them 
over, I seem to remeber these being used on the Commodore PET.

Cheers.

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.