[Coco] R+DOS/16 IDE support: I learned about the $052DDC offset the hard way.

[Tormod Volden]

Hi Juan,

Is 052DDC some kind of standard value? In case it maybe should be
applied to HDB-DOS proper. Are there other common values?

I looked through your patch and it it looks indeed less invasive than
what I have seen before. But what changes in this patch require going
to 16K?

I am however inclined to keep HDB-DOS conservatively to 8KB and rather
let people explore Brett's new DOS for everything that one can do with
16KB.

Regards,
Tormod




On Sun, Apr 5, 2015 at 2:09 AM, Juan Castro <jccyc1965 at gmail.com> wrote:
> I tried to use a compiled-from-sources 16 KB LBA HDB-DOS ROM with my
> BASIC goodies in my MiniIDE, and got nothing. Then I remembered about
> the FF70 port thing, changed it to FF50 -- nopw I got gibberish from
> the disk instead of a lockup.
>
> I backtracked EVERY change in the ROM, one by one. At some point I
> even thought the recent TFSIDE patch was the culprit. After taking
> everything out (and burning some 20 EPROMs in the process). After much
> disappointment, I got to a difference of 3 bytes between my compiled
> ROM and the one that worked.
>
> Those bytes were 00 00 00 in my ROM, and 05 2D DC in the working ROM
> that came with the MiniIDE. Yeah. Hard-coded sector offset.
>
> Now I FINALLY have a 16K HDB-DOS derivative for the CoCo 1/2 with the
> BASIC enhancements I had before (except DW support) working on an IDE
> interface. It should work in a Glenside IDE or a SuperIDE if you can
> coax the hardware into seeing a 16K Disk ROM. Here's it:
>
> https://dl.dropboxusercontent.com/u/15643089/16k-hdblba.rom
>
> And below is the source patch. On its face, it's a less invasive patch
> -- it just creates 16k ROMs and leaves disk support as-is. I imagine
> ROM 16k-xxxxxx.rom should work pretty much as well as the plain 8k
> xxxxxx.rom, for every xxxxxx.
>
> https://dl.dropboxusercontent.com/u/15643089/16k-ide-rom.patch
>
> Next challenge is to reintroduce DW support into an IDE ROM as an
> add-on. That will be tricky, but, I imagine, less than introducing IDE
> support into a DW ROM.
>
> Also, I didn't hack my MiniIDE; I used an MPI.
>
> Juan Castro
> Enviado do meu Olivetti Programma 101
>
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