Date:         Tue, 25 Aug 1992 10:20:30 PDT
Comments:     Warning -- original Sender: tag was NETNEWS@UVVM.UVIC.CA
From:         Melvin Klassen <KLASSEN@UVVM.BITNET>
Subject:      Re: Zmodem for VM/CMS

"Matthew E. Bernold" <MEB117@PSUVM.PSU.EDU> writes:
>Sorry if this is the wrong place to post this, but I'm looking for a Zmodem
>implication for the VM/CMS system running on an IBM mainframe.

You won't find one, if postings from other mailing-lists can be believed!
________________________________________________________________________

Date:         Mon, 19 Aug 1991 16:42:00 CDT
X-Sender:       VM Utilities Discussion List <VM-UTIL@OHSTVMA>
From:         Neil Erdwien <NEIL@KSUVM>
Subject:      Re: ZMODEM and KERMIT

>Is there any IBM VM/CMS program enabling ZModem file transfer
>between the mainframe and a PC?

ZMODEM: I know of no CMS implementation.  ZMODEM gets some advantage by
using the full duplex nature of most PC/Unix connections.  Because the typical
IBM front-end hardware can't do this, ZMODEM would help you little.

I'm sure many people will respond to this -- KERMIT has some friends!
I routinely get transfer rates over 90% of theoretical maximum, e.g.,
900 chars/sec on a 9600 BPS line.  If you want noticeably faster transfer,
you are going to need a faster transmission channel.

Be sure you are using long packets -- I use 1900 bytes per packet.
KERMIT also *DOES* do error correction.


Date:         Wed, 21 Aug 1991 15:05:00 EDT
From:         "John F. Chandler" <PEPMNT@CFAAMP.HARVARD.EDU>
Subject:      Re: ZModem for IBM VM/CMS system

> I want to ask you if there is a VM/CMS port for X,Y,Z-Modem.
There will almost assuredly never be any such products for CMS.
Those programs assume some things that don't hold in most IBM/370-type
systems: full-duplex, two-way 8-bit data channel.  The foremost
assumption is that of full-duplex transmission -- IBM mainframe
architecture simply is incompatible with it, so that's just not going
to happen (don't be confused by the possibility of type-ahead on
protocol converters -- they aren't the mainframe).


Date:         Tue, 3 Mar 1992 12:53:44 PST
From:         "Russell N. Hathhorn, VM Systems Support" <SYSMAINT@PCCVM>
Subject:      where to find ZMODEM VM/CMS program ?

You can find a VM/CMS Zmodem protocol in the same location as a
'MUFFLER BEARING' factory.


Date:         Tue, 3 Mar 1992 21:08:50 GMT
From:         "Korey J. Kruse" <kkruse@MATT.KSU.KSU.EDU>
Subject:      Re: where to find ZMODEM VM/CMS program ?

This has come up before.  Kermit is the only protocol that VM/CMS supports.
This is because VM/CMS runs 7-bit data, with parity even with
half-duplex (not sure about this last setting).   Kermit is available
free for both VM/CMS and for the dial-in computers, Apple, IBM PC, and
a slew of others.   ZMODEM just won't work.


Date:         Fri, 20 Mar 1992 22:49:22 CST
From:         Rich Chong <U41602@UICVM.UIC.EDU>
Subject:      Re: where to find ZMODEM VM/CMS program ?

Sorry for a late reply on this... lets get things clear...
Kermit is not the only [file transfer] protocol CMS supports.
There are other vendor ones like Relay Gold's and IBM's IND$FILE.
It's not because VM/CMS runs 7bit even-parity, as a matter of fact,
that dependency is more the front-end processor (7171, 3705, Hydra, etc)
definition. Right now I'm using a 9370 ascii subsystem FEP into a VM
system at 8-bits no-parity no-problem ;-). Actually, ASCII is really
only a 7-bit thing with parity, and people used that so much that
another parity bit is sometimes used. IBM mainframe EBCDIC was always 8.
The half-duplex nature of a real 3270 fullscreen (or IBM's old TTY)
protocol is the main show-stopper. Now this isn't to be confused with
the half/full duplex of your PC's comm. program or your modem. Those
basically have to do with where the character may get echoed back
(locally, remotely, not) rather than if the line really duplex capable.
The problem is that the ASCII streaming protocols (X/Y/ZMODEM,etc)
require a real full-duplex mode. Basically, this means that data can
flow both ways at the same time. A streaming protocol basically shoots
data down a line and won't stop until it's done or it hears that there
is an error detected from the other end. In a real half-duplex line,
this notification is not possible if one side is a jabbermouth.


Date:         Mon, 23 Mar 1992 18:51:00 EST
From:         "John F. Chandler" <PEPMNT@CFAAMP>
Subject:      Re: where to find ZMODEM VM/CMS program ?

> Kermit is not the only [file transfer] protocol CMS supports.
True, but it's the only protocol supported by other types of computer as well.