[Coco] Xmodem, Ymodem

[Gene Heskett]

On Saturday 22 March 2008, George Ramsower wrote:
>I'm curious why Ymodem won't work between this PC XP-Pro SP2 and my coco
>OS9-L2
>
>Xmodem works, but places stuff at the end to fill in the last 100 bytes(I
>assume)
>I can't get Ymodem or Zmodem to work at all. So, what I do is just edit out
>the extra crud that xmodem adds and the end and go from there.
>
>I don't use a terminal program on the coco. I simply do "shell i=/t2&" from
>the coco in the startup file and use Hyperterminal on this PC to do my work.
>Well, actually right now, I'm using /T3 on the coco because I lost a driver
>or reciever on the coco on the /t2 port. I need to fix that. This happens
>about once a year.
>
>I run it at 9600 baud, 8n1, using using all the handshaking lines such as
>RTS, CTS and RD
>
>The Xmodem and Ymodem routines I have came from the OS9-L2 BBS system I
>bought about a thousand years ago.
>
> This has been a problem since day one. I read on this list that another
>person(I can't remember who) said he couldn't get Ymodem (or maybe Zmodem)
>to work either.
>
> Suggestions?
>
>
>George

What version of zmodem, George?

AFAIK, rzsz-3.36, the last one I built, should work against any other zmodem 
extant unless mickeysoft has "improved" it somehow on the pc end. 3.36, 
running on nitros9/6309 machines can keep a 9600 baud port fairly busy.  I 
was getting around 7400 baud. zmodems crc calculations on a per byte rx'd 
preclude even thinking about getting ymodem speeds, but they also guarantee 
data purity.  On noisy phone lines 10+ miles from the CO, I never had a 
binaries crc get trashed.  zmodem error recovery restarts on a per block 
basis of course, but never any bad data on the hard drive when it was done.  
zmodem can also restart where it left off if you get disconnected, see the 
help screen when you make a mistake for that syntax.

OTOH, I can't get it to work here either, but that (I think) is because I 
don't have the right descriptor in my bootfile for '7 wire' handshaking.  
RTS/CTS flow controls in other words.  I've asked here, but it seems to be a 
lost art, no one has pointed me to a working /t2 & sacia (or aciapak) 
descriptor.  Or maybe I have 1488/1489 problems in the rs232 pack?  I can 
type back and forth from machine to machine most of the time, but file 
transfers fail within 10 bytes and eventually give up.

Humm, thinking out loud here, the last time I tried that, I was using a pl2303 
based usb<->serial adapter, and we've since found its a POC, won't work with 
roadnav, and won't work with heyu about 10% of the time. I should try that 
using an FDTI adapter as they work quite well.

-- 
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)
Conscience is the inner voice that warns us somebody may be looking.
		-- H.L. Mencken, "A Mencken Chrestomathy"