[Coco] Need help with 3.5" drives and NitrOS-9

[Robert Gault]

Willard Goosey wrote:
> When the 6809 Nitros releases first started coming out with this $21 DNS setting for 3.5" drives I decided to ignore it because I have approximately 100 dsdd 3.5" OS9 disks and I didn't feel like patching them all. Much easier to patch the occasional descriptor.
>
> I don't know what your driver is doing different but it's obviously a software problem. Drive data rate is not tied to tpi. A 135 tpi DD disk is written to at the same speed as a 48 tpi DD disk.
>
> Willard
> Sent from Samsung tablet
>

Willard,

That's what I found empirically and what Gene says; use 48tpi. The problem seems 
to be the way rb1773.asm is written which considers 96tpi and 135tpi to be 
treated the same and differently from 48tpi.

In short we need to revise something. The easiest thing would be to make typ=$20 
for both 5.25 standard OS-9 disks and 3.5" disks. But if that were done, you 
would get misleading messages from the format command.

It looks as if the optimum solution (if indeed there is one) for this specific 
problem would be to change rb1773 so that it changes behavior when it sees 96tpi 
somewhere in the descriptor but handles 48 & 135tpi the same way. Unfortunately 
there is no indicator for tpi but only 5.25 and 3.5 inch disks. The size of the 
disk clearly is irrelevant while the track density is what is important.

So now we are faced with two issues, backwards compatibility and badly written 
sections of rb1773/rb1773desc. While I hate to see bad code in NitrOS-9, I don't 
see a solution that does not involve individual tweaking of the descriptors or 
rb1773 by users.

We need an executive decision on this or live with chaos. :) Who wants to decide 
in the absence of Boisy? :)