Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!decwrl!palo-alto!vixie
From: vixie@palo-alto.DEC.COM (Paul Vixie)
Newsgroups: comp.dcom.lans
Subject: Re: U-B Terminal servers flame
Message-ID: <3461@palo-alto.DEC.COM>
Date: 16 Jul 88 03:40:29 GMT
References: <320@ucrmath.UUCP> <9877@g.ms.uky.edu> <23731@bu-cs.BU.EDU> <23841@bu-cs.BU.EDU>
Organization: DEC Western Research Lab
Lines: 31
In a previous lifetime, I worked with quite a lot of U-B equipment :-).
The thing I liked about it was that it did full-duplex RTS/CTS hardware
handshaking. This means that you can take an NIU-130 or -180, hook Telebit
Trailblazer + modems up to it (with a special U-B adaptor cable), tell the
TT+ to use full-dup RTS/CTS, and never worry about ^S/^Q again. It's great
for a modem which sometimes runs in UUCP spoof mode (which needs no flow
control because it's a windowing lock-step) and normal 'tip' which needs
lots of ^S/^Q because the modem is usually talking to you at a different
baud rate than its carrier calls for.
The NIU-DMF32 (yes, I know that DEC makes a product by this name, but this
is an Ungermann-Bass NIU-DMF32 I'm talking about) is a pretty clean way to
attach a Unibus machine to a U-B network, except that the one part of the
DEC DMF32 interface spec that U-B didn't implement was FIFO. (Note that
this would have been trivial since they get packets with several characters
in them when the speed is high enough.) The CPU gets an interrupt for each
and every character received over a UB NIU-DMF32, and the driver is _not_
optimized for this case because (1) real DMF32-type devices have FIFO's,
and (2) U-B hadn't thought of or heard of Telebit modems when they designed
their NIU-DMF32.
I've wondered if the NIU-130/180 were talking telnet to a DEUNA, whether it
would perform better than when it speaks XNS to an NIU-DMF32. I suspect
that some problem in telnet would make UUCP work poorly.
Note: DEC doesn't know I'm sending this, so don't go suing them.
--
Paul Vixie
Digital Equipment Corporation Work: vixie@dec.com Play: paul@vixie.UUCP
Western Research Laboratory uunet!decwrl!vixie uunet!vixie!paul
Palo Alto, California, USA +1 415 853 6600 +1 415 864 7013