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