Re: Commodore 15 Second disk format routine disassembled

From: Francesco Messineo <*francesco.messineo_at_gmail.com*> Date: Fri, 19 Jun 2026 15:23:31 +0200 Message-ID: <CAESs-_wy6Z76kgkMxAwHtC=7E+tZxHvg5hTuvSdM35BUvxRuTQ_at_mail.gmail.com> · francesco.messineo_at_gmail.com

On Fri, Jun 19, 2026 at 3:14 PM Maciej Witkowiak <ytm_at_elysium.pl> wrote:
>
> On Fri, Jun 19, 2026 at 2:16 PM Francesco Messineo <francesco.messineo_at_gmail.com> wrote:
>>
>> let me change slightly the question: how does the firmware pack 21
>> sectors on the smaller tracks without running out of space?
>
>
> It just never changes the speed zone setting

yes yes, now I've engaged the brain and I get what it does. Of course
it works but I suspect it won't be super reliable every time.
Transitions per inch-wise it's well within the magnetic media
possibilities, it would just need a better magnetic head but maybe
1551 mechanisms had a much better head than the shugart 400 drive that
set the limits of the original 3040/1541 format.

Thanks
IZ8DWF