[Coco] PBJ PC PAK - Part II - Interfacing (source for driver)
gene.heskett at verizon.net
Thu Jan 31 21:01:31 EST 2008
On Thursday 31 January 2008, Mark McDougall wrote:
>Gene Heskett wrote:
>> Not impossible, but it will be time consuming to run all
>> those defines down and figure out what its doing.
>"Byte-bashing" IDE (for lack of a better term) with a suitable hardware
>interface really is quite trivial and doesn't require a great deal of code
>(especially PIO mode). The only tricky part is complying with the timing on
>the status register - not reading it too *soon* rather than too late - so on
>older hardware it's probably not so much of an issue.
>So it's probably better to roll your own from scratch rather than attempt to
>port the linux driver to os9/nitros09?!?
If one knows the hardware at the register level, it does seem like it would be
better done in assembly to me just because it is going to be less wastefull
of the coco's limited resources.
But bear in mind, the number of hours I have run an rsdos program over the
history of the coco is probably under 50 hours total, I was os9, then
nitros9, from level 1 version 1.00.1 on an old grey ghost through a 2
megabyte, 6309 equipt coco3, till the amiga gradually took over.
Not all of the code I've posted on rtsi is assembly, probably as much was in
C, with a trace or 2 of basic09. The single most often used piece of code I
wrote never got out of the tv station, a basic09 program that ran on a level
one system, and which blew a similar function sold by the Grass Valley group
for $20,000 completely into the next drainage. That code was probably run 5
to 15 times a day as the various tech directors doing commercial production
were reloading each of their personal bag of tricks into a programmable
GVG-300-3A/B video & digital effects mixer. And it did this for nearly 15
years, blowing 3 controllers and wearing out 3 or 4 floppy drives in that
time. Written in Basic09, it was still 4x faster than GVG's high priced
I relate that not to blow my horn, but mainly to show that as for rsdos or
rsbasic, I'm relatively inexperienced and will defer to those who have run
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