[Coco] 3.5" FD drives

[Barry Nelson]

 I have had the following experience. I have a Commodore 128 have a 1581 3 1/2 inch drive that I used to use before I hooked up an IEC2SD SD card interface. I had a shortage of 720k disks and so I would tape over the HD hole and put the disks in a linux server and write the Commodore disk images out to actual disks. I found typically that after that if I read those disk in the Commodore 1581 drive they worked fine, but if tried to write to them it worked 90% of the time. If I tried to reformat them in the Commodore, it might take 2 or 3 attempts, and then they would work ok and I could write to them fine. Low density disks worked without any issues. Degaussing the HD disks does help. These issues were trivial and did not prevent me from effectively using HD disks.

On Jul 25, 2015, at 1:18 AM, coco-request at maltedmedia.com wrote:

> Date: Fri, 24 Jul 2015 23:09:17 -0500
> From: Dave Philipsen <dave at davebiz.com>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Subject: Re: [Coco] 3.5" FD drives
> Message-ID: <55B30BED.2030507 at davebiz.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> There is a lot of discussion on this if you search the internet.  I have 
> personally found that you can write DD disks in a HD drive without 
> problems.  Others swear that you'll have a problem.  Since the HD 
> floppies generally require a higher recording strength to store data at 
> that density it makes sense that perhaps a DD controller may not have 
> enough power to overcome a pre-existing HD format.  So it may be better 
> to use non-formatted disks that have never been used to record HD.  You 
> might also improve your chances by bulk erasing (degaussing) an HD 
> diskette before using it as DD.
> 
> Read "A note on DD and HD 3.5" disks here: 
> http://www.soundtracker.org/raw/cwfloppy/
> 
> Another good discussion here: 
> http://www.retrotechnology.com/herbs_stuff/guzis.html
> 
> 
> Dave