Re: Commodore 15 Second disk format routine disassembled

From: Francesco Messineo <francesco.messineo_at_gmail.com>
Date: Fri, 19 Jun 2026 14:51:30 +0200
Message-ID: <CAESs-_zVA_MNLwm7RtwS_EwTfCqS+Urbah6R94z7-i+Vk2ak3A_at_mail.gmail.com>
On Fri, Jun 19, 2026 at 2:45 PM André Fachat <afachat_at_gmx.de> wrote:
>
>
> Correct. The only difference is that due to the smaller tracks the bits on the media get smaller two. Eventually reaching a point where the quality of the material (e.g  granularity of the magnetic material) makes it unreliable.
>

it's not the material, it's the head's pole gap that are too large.
100 tpi heads (or 96 tpi ones, they're identical) have a much smaller
magnetic gap. So with even higher clock rates, 8x50/SFD-1001 drives
can format 29 to 23 sectors on the same magnetic media, and I've read
without errors disks written in 1986 with the SFD-1001.

IZ8DWF
>
>
Received on 2026-06-19 14:00:57

Archive generated by hypermail 2.4.0.