[Coco] Serial Port file transfers

[L. Curtis Boyle]

On Mon, 06 Nov 2006 00:30:52 -0600, Gene Heskett  
<gene.heskett at verizon.net> wrote:

> On Sunday 05 November 2006 23:03, Jim Hickle wrote:
>> What sort of speeds should I be expecting from a 512k CoCo running
>> NitrOS9, with an RS-232 pack connected to a Linux system's serial port?
>> I'm trying to transfer files and it's taking forever using floppies and
>> the PCDos program.
>>
>> Using rz/sz on the coco I can set the ports no higher than 2400 bps.  I
>> can bump it up to 4800 if transferring using Supercomm's Xmodem
>> transfer.  Is this really the limit?   Maybe I should give up on serial
>> transfers and use CD-ROM's?
>>
> Years ago now, I was using an amiga-2000-040 and Olaf Barthels term4.7 to
> measure that.  I was getting around 740 cps with the interfaces set for
> 9600 on a nitros9-1.15 system, and about 430 cps with a stock 512k coco3.
> This was using the auto-trigger of rz/sz-3.36 with supercom-2.3 for the
> term program on the coco3's.  Using the 7-wire protocol for flow control,
> not xon/xoff.
     This was using Nitros9 as originally intended on a 6309 chip... I  
don't know if Jim is using a 6809 or 6309 chip in his scenario. I know I  
used to get about 700-800 CPS with a 9600 connection with RZ/SZ (which  
really needs a rewrite to use proper buffering to speed it up), and with a  
38400 connection (Eliminator from Frank Hogg Labs), I could get 2000+ cps  
with Ymodem/Ymodem batch. If you have the Randy RS-232 pak, then about  
1700-1800 cps would probably be the max with X/Ymodem (x is slower, since  
it has more overhead) using a decent term program like Supercomm or  
OSTerm. Once again, running the 6809 version of Nitros9 might be a bit  
slower; I am basing on the 6309 version.


>
> Using xmoden or ymodem, speeds in the 3000 or more cps range should be
> doable on a stock coco3 since they have a much simpler error checking
> method and send whole 128 byte blocks at a time whereas rz/sz is  
> character
> at a time which makes its 24 bit crc checking a huge cpu hog.  But, rz/sz
> absolutely guarantees the data sent is good, the other two methods can  
> let
> errors slip thru, and file sizes need trimmed as they record whole 128
> byte blocks even if the last byte of the file is the first byte of the
> last block, which makes the rx'd file 127 bytes too long.

    Y-batch also does exact file sizes correctly, like Z, as well as  
multiple files in a single transfer.

>
> If you can't set the ports any higher than 2400 baud, you have a flow
> control miss-match I think.  And because the acia chip has a bug, there
> was a minor re-wire of the rs-232 pack and a patch for sacia that fixed
> that bug if you wanted to use hardware flow control, commonly called
> 7-wire.  That patch should be in the later sacia modules, its enabled by
> one of the xmode options and isn't documented anyplace but in that  
> patch's
> readme that I know of.
>
> Unforch, I don't recall the name of the patch, and I'm not sure that it
> survived the hack job when rtsi got hacked into several years ago.  I
> don't believe I have it myself now, as it was a casualty of a flaky hard
> drive & controller a decade+ back up the log.
>
>> -jim hickle
>>
>>
>>
>>
>> ---------------------------------
>> Get your email and see which of your friends are online - Right on the
>> new Yahoo.com
>



-- 
L. Curtis Boyle