Re: Commodore 15 Second disk format routine disassembled

From: Maciej Witkowiak <*ytm_at_elysium.pl*> Date: Fri, 19 Jun 2026 15:11:42 +0200 Message-ID: <CAB+mWqu7u3wB-gXRtUgXq4hrvdAFErzRU=jknLvCHZWmVr+1Jg_at_mail.gmail.com> · ytm_at_elysium.pl

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.

> If you have a flux image of such a formatted floppy, I'd like to see it.

Here it is, with visualizations:
https://drive.google.com/drive/folders/1tRTF9O-fUw-T_BHFQjs6CXtBiHt8590Q?usp=sharing
Note that it doesn't come from a real floppy - it's an image from Pi1551
emulation

ytm