Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watnot!watmath!clyde!cbatt!ucbvax!WILLIAMS.BITNET!WITLICKI From: WITLICKI@WILLIAMS.BITNET.UUCP Newsgroups: mod.computers.vax Subject: Re: Vax I/O Message-ID: <8703041923.AA07284@ucbvax.Berkeley.EDU> Date: Wed, 4-Mar-87 14:24:01 EST Article-I.D.: ucbvax.8703041923.AA07284 Posted: Wed Mar 4 14:24:01 1987 Date-Received: Fri, 6-Mar-87 04:19:32 EST Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 29 Approved: info-vax@sri-kl.arpa Rob Cote writes: >I am trying to find out whether a VAX can handle a synchronous 4.8 Kbit >input line. We have either a VAX 750 running UNIX 4.2 BSD or a MicroVAX >II/GPX also running UNIX 4.2 BSD. The line we will be using is a news >wire service, similar to the AP news wire and will plug into either a >DH or DZ panel (I think). We are trying to avoid using >an IBM PC as a dedicated head to pre-process the line and buffer the >the data stream before passing data to the VAX. Anyone out there >have any useful information? Thanx. A while back I was at a site where we wanted to read a 1200 baud news wire into a DEC 2060. There were about 40 or so 9600 baud terminals hardwired into the PDP 11/40 front end. During the midafternoon rush if N users did screen refreshes at once there was no way the front end could keep up with the news wire input. Since you can't poke a control-S at the news wire you *have* to be able to take all the characters as they come in or else throw them on the floor. What I ended up doing was taking an old 8K PDP 11/20 that was lying in the corner, added two serial ports, wrote about 150 lines of PDP/11 assembler and about 50 lines of Bliss code on the 2060 (which later grew as we processed headers). I'm sure a 750 or a uVax II can handle the 4.8 kbit line if that's all or almost all it's doing. How much other I/O can it do in addition to the news wire?... I've always had to experiment with this kind of thing. A dedicated front end may *have* to be your solution if you want to handle any sort of real interactive load. - randy