[Coco] DW and 6551

[Allen Huffman]

> On Feb 10, 2015, at 5:35 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:
> 
> There was a driver at one point, but I don't think anyone maintains it and
> so I don't think it was converted to the modular system we started using a
> while back.  In the time since that document was written I think it's
> realistically changed to "not supported".  Writing a driver for the 6551
> would not be very difficult but since it's so limited in speed compared to
> the bitbanger I think there is little interest.

At a reduction of speed, would we get better responsiveness by using the hardware, though? I was stunned to find that I could use 9600 baud on /t1 a few nights ago. If I typed real fast it would glitch a character, but it was working. I knew this was easy in RS-DOS, but thought the bitbanger code was limited to like 1200 or so.

BUT, it really chewed up the system and made everything hang and pause. I note that bitbanger DW does the same thing, which is fine if you aren’t multitasking but I tend to always be doing something. I wonder if the RS232 pak would be a good tradeoff — less IRQ masking but slower disk transfers.

One of the big myths back in the day was the limit of the bitbanger. It was rare to see terminal programs that went very fast, but Ultimaterm (and probably Sockmaster’s) proved it could be done. We used a remote drive written by Ken Johnson (Johnston?) who wrote Ultimaterm and it went to a higher baud rate than anything we knew about - - complete with a typeahead buffer in BASIC.

I was very impressed /t1 could do that kind of stuff now — I am guessing it got upgraded because of new knowledge gained from DW? Or has it always worked and we were just told it was impossible so we never tried?

		— A