Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!ginosko!brutus.cs.uiuc.edu!psuvax1!rutgers!netsys!faatcrl!jimb
From: jimb@faatcrl.UUCP (Jim Burwell)
Newsgroups: comp.dcom.modems
Subject: Re: HST and uucp
Keywords: uucp / hst
Message-ID: <1040@faatcrl.UUCP>
Date: 14 Oct 89 04:50:06 GMT
References: <[2535d5d4:17]comp.dcom.modems@nstar.UUCP>
Organization: FAA Technical Center, Atlantic City NJ
Lines: 56

akcs.larry@nstar.UUCP (Larry Snyder) writes:

>Is anyone use the HST for UUCP transfers?

>My PEP gets 1450 cps sending mail via UUCP using the built in UUCP.
> 
>My HST gets 230 cps sending mail via UUCP to another HST - and both
>modems are locked yet produce 1550 cps when connected via ProYam
>doing a Zmodem - Zmodem transfer.
> 

>Ideas?  Suggestions?

It's not your modem, nor your connection.  It's the protocol.  UUCP's 'g'
protocol is a block/handshake type protocol like XMODEM.  Everytime the
modem sends a block (I think they're 32 bytes) it needs a handshake from
the other end telling it to send the next block..   On full duplex modems,
that's fine...  But on modems like the Telebit TBs, and USR HSTs, which
are half duplex, it will NUKE your CPS..  This is because they "turn the line
around" when they need to send data back in the other direction..  This can take
a bit of time.

Telebit got around this problem by building uucp 'g' "spoofing" into thier 
modems.  You set the protocol to uucp, and the modem detects when a 'g' 
transfer starts.  The modem negotiates the 'g' protocol with the computer,
and sends the data it's collected to the other Telebit with it's native PEP
protocol.  The recieving modem does likewise.  That's why Telebit's get great
'g' protocol throughput..

As far as I know, USR hasn't built any kind of protocol spoofing into its HSTs.
Therefore you take a big performance hit when you use a handshakeing protocol
like 'g', xmodem, ymodem, or Kermit..  Zmodem transfers get great CPS times since
it is a streaming protocol, which doesn't do any handshakeing unless there is
an error, or you've hit EOF..


There's not much you can do but get a Telebit, or maybe try some of uucico's 
other protocols..  Since the HST is capable of an MNP error free connection,
you may be able to use a protocol which doesn't do any error checking, or hand
shakeing during the transfer..  Look into 't' and 'f'...


-- 
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|          James S. Burwell                      |                          |
|                                                | "UseNet...A text network |
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