Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site watdcsu.UUCP Path: utzoo!watmath!watnot!watdcsu!herbie From: herbie@watdcsu.UUCP (Herb Chong [DCS]) Newsgroups: net.wanted Subject: Re: IBM 3270 Emulation under Un*x Message-ID: <1491@watdcsu.UUCP> Date: Thu, 20-Jun-85 16:43:35 EDT Article-I.D.: watdcsu.1491 Posted: Thu Jun 20 16:43:35 1985 Date-Received: Thu, 20-Jun-85 23:48:59 EDT References: <545@rlvd.UUCP> <1023@mnetor.UUCP> <1484@watdcsu.UUCP> <1047@mnetor.UUCP> Reply-To: herbie@watdcsu.UUCP (Herb Chong [DCS]) Organization: U of Waterloo Lines: 51 Summary: In article <1047@mnetor.UUCP> clewis@mnetor.UUCP (Chris Lewis) writes: >Thanks for the info. Is that the one that IBM promotes for their >customers? (Eg: is this the one that VM/IX requires?) yale is not the system required to run VM/IX because the software is wrong. the hardware requirements are the same though (more or less). >I think Herb means CPU "resources". SIM3270 only needs the standard >ASCII => IBM hardware (a 3705 and/or COMTEN etc.). So, if you already have >ASCII terminal access, SIM3270 is a lot cheaper, but may impose some >added IBM CPU penalties because it uses a separate virtual machine to handle >the terminals. I think that the performance impact on the BNR system >(3033 with 250+ simultaneous users) was slight to insignificant - but >not all that many people used it simultaneously. Anybody contemplating >either will have to do their own evaluation. the performance penalty is not that high, but running half duplex sucks if you are used to full duplex or real 3270's. with our tightly coupled network of 2 4381's and 2 4341's, the performance penalty is minimal because the terminals are slow enough that the byte multiplexor channels are relatively lightly loaded. note that the virtual machines running SIM3278 are not run prefered in any way on our system and screen response is still about as fast as one can expect on 2400 BAUD lines even when the system is heavily loaded. if you are starting from scratch and already have ASCII hardware but no series/1 machines, SIM3278 is probably your best bet. if you want to go into ASCII support on your mainframes in a BIG way and have a LAN that supports at least 4800 baud, then going the Yale approach is the highest performance alternative. on an average day on our system, we have about 400 users on our network (watdcs is really 4 machines running with single system image SSI software). of these, about 45% are using yale, 40% are using SIM, and about 10% using real 3270's. a tiny fraction use direct ASCII dialup. I should mention at this point that Sytek is capable of video bandwith, so transfering data at about one megabit/s rate between your ASCII system and your series/1 controller is possible provided that both ends can handle the data transfer rate. also, with appropriate software on your IBM PC's (DOS 3.1) and hardware (network adaptors) you can use the same LAN to network your PC's. we have run demos on our Sytek network with a video source transmitting to various monitors about the campus. Herb Chong... I'm user-friendly -- I don't byte, I nybble.... UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!water!watdcsu!herbie CSNET: herbie%watdcsu@waterloo.csnet ARPA: herbie%watdcsu%waterloo.csnet@csnet-relay.arpa NETNORTH, BITNET, EARN: herbie@watdcs, herbie@watdcsu