JEWIL@UCONNVM.BITNET (Stephen Williams) (11/21/89)
Gentlemen:
I have made a cursory inspection of the various archives
available to me and have found nothing that looks to be an
implementation of the ZModem file transfer protocol for the
VM/CMS system.
Currently I am using YTerm 2.1 on a PC which serves as an
excellent communications package. However the mainframe file
transfer module (PCTrans 1.3) appears to handle transfers in
small non-variable blocks of between 300 and 400 bytes which I
would suspect to be slower than a streaming transfer protocol
such as ZModem.
And so, the questions:
I. Does anyone know of an implementation of the ZModem protocol
for the VM/CMS system?
II. Does anyone have any knowledge of the ease (or
impossibility) of modifying an application of ZModem to work
on VM/CMS?
III. Can anyone shed a more educated light on my suspicions that
ZModem would offer improvements over the currently available
file transfer protocols? (I have had little experience with
the more commonly used Kermit but suspect that it operates
similarly to PCTrans.)
All inputs, no matter what the block size, will be greatly
appreciated.
S.
=================================================================
Stephen J. Williams
12 September Road SWILLIAM@UCONNVM.BITNET
Storrs JEWIL@UCONNVM.BITNET
Connecticut 06268-2806 (203) 456-1268
=================================================================
Acknowledge-To: <JEWIL@UCONNVM>JEWIL@UCONNVM.BITNET (12/23/89)
Greetings,
I recently posted an inquiry to this and other lists looking
for information on the ZModem possibilities on VM/CMS. This is a
report my findings and a thank you note to those who added there
twenty-five cents worth.
ZModem for VM/CMS does not exist. The primary reason is
that most mainframe communications take place at 7 bits. (The
only exception that I know of is ASU which expects 8 bits.) If Z
could be implemented it would offer significant savings, even as
compared to the best available file transfer protocol (Kermit
with the packet size set to 1K).
The universally held opinion is that ZModem needs 8 bits and
cannot be modified to run on 7 (this information confirmed by a
high Z source [thanx Jeff]). Therefore until many of the
mainframe systems (including UConn) follow ASU's lead and switch
to 8 bits (hint Steve) there is not likely to be a ZModem for
VM/CMS.
My thanks to all those who shared what they knew and my
apologies for taking so long to respond.
S.
=================================================================
Stephen J. Williams
12 September Road SWILLIAM@UCONNVM.BITNET
Storrs JEWIL@UCONNVM.BITNET
Connecticut 06268-2806 (203) 456-1268
=================================================================
Acknowledge-To: <JEWIL@UCONNVM>