[Coco] Preserving old CoCo diskettes...

[Aaron Wolfe]

On Tue, May 18, 2010 at 4:49 PM, Gene Heskett <gene.heskett at verizon.net> wrote:
> On Tuesday 18 May 2010, Roger Taylor wrote:
>>At 02:04 PM 5/18/2010, you wrote:
>>>Roger, why not contribute that code to the nitros9 project?
>>
>>I didn't write an rz/sz protocol that could work at 115200 or 230400
>>bps.  My point was that if you can't get those old programs to work,
>>move on to a new idea using the least number of chip signals as
>>possible.  Hence, a software solution.
>
> rzsz is a separate problem, which is why I mentioned other protocols as being
> faster, much faster.
>
> Since I compiled the rzsz you are, or have played with, I can't argue that
> its architecturally wrong, it is, and that means you are limited to a hair
> over 700 cps on a 6309 machine, and the middle 500's on a 6809 machine.
> It is, in the face of poor line quality, absolutely bulletproof though.  It
> just keeps on hammering until the checksums do match.  The problem is that it
> builds the checksum one &^% char at a time, so that whole loop has to execute
> for every incoming byte.  Grrr.

Running some tests using rz over a DriveWire 4 virtual serial port
reveals that it can maintain ~1100 cps on my 6309.  Although DW
provides some alternate ways to transfer data that are much faster, if
zmodem is a requirement, you might want to consider using the
bitbanger+dw4 instead of the 6551, as strange as that may seem.

>
>>I've found it a much better experience to just mount remote .dsk
>>images and have the files sitting right there in native DOS or OS-9
>>format already good to run or copy.
>
> That sounds like a better idea, but I'm not sure I know how.
>
>>>I might be able to do a new driver based on what I have learned thrashing
>>>about in the mud pit of this one, and come up with a totally different
>>> design that works only against this linux box.  That wouldn't be very
>>> good.  If you have a wheel that works, lets beat on it and maybe make it
>>> the std version. Everyone would benefit, including you because the driver
>>> would already be in the OS distribution.
>>
>
>
> --
> Cheers, Gene
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Barbie says, Take quaaludes in gin and go to a disco right away!
> But Ken says, WOO-WOO!!  No credit at "Mr. Liquor"!!
>
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