[Coco] OS9 display server added to DW4

[Aaron Wolfe]

On Wed, Jun 27, 2012 at 11:51 AM, Allen Huffman <alsplace at pobox.com> wrote:
> My Sub-Etha Software partner, Terry Todd, also wrote one for RS-DOS that did that. At the time, he had plans of trying to make it handle graphics modes and the mouse, but we never got to it. I forgot all about that.
>
> I think I did see the PC version running at a Fest once. I also forgot all about that.
>
> I rewrote my EthaWin text GUI to have a mode to just pass control codes so it would work over Terry's terminal program -- no mouse, but you could use ALT-keys to access the menus and pop-ups and such.  I think the main thing was not having the app manually open up a new /w window to use.
>
> This was later reused when I ported the OS-9/68K MM/1 version of EthaWin (and the Towel disk utility) to work via Termcap. I wrote a wrapper library that emulated most of the C3Windowing control codes (overlay windows, etc.).
>
> -

I had originally thought about trying to do translation between the
os9 calls and vt100 or ansi right in the scf driver, and then let that
driver map I/O to another 'real' driver like /Tx or /Nx.  That would
be a really nice universal solution to the lack of terminal support
generally found in os9.   However, it turns out such a thing (layered
drivers) is really hard to do in OS9, if not impossible.. at least
that is the story I got from people who know a lot more than I do
about it.   It's unfortunate because there are some other things that
could be nicely implemented as drivers that sit in between a process
and another driver, but you have to drawn the line somewhere and
generally I think the OS9 guys did a heck of a nice job deciding
where.