Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!uw-beaver!ubc-vision!van-bc!sl From: sl@van-bc.UUCP Newsgroups: comp.unix.xenix Subject: Re: Wanted: Suggestion for 286==>386 Message-ID: <1595@van-bc.UUCP> Date: Fri, 4-Dec-87 04:58:27 EST Article-I.D.: van-bc.1595 Posted: Fri Dec 4 04:58:27 1987 Date-Received: Thu, 10-Dec-87 01:01:09 EST References: <7560@eddie.MIT.EDU> Reply-To: sl@van-bc.UUCP (Stuart Lynne) Organization: Public Access Network, Vancouver, BC. Lines: 91 Keywords: 286 upgrade 386 inboard cheap-386 tofu In article <7560@eddie.MIT.EDU> mdc@eddie.MIT.EDU (Marty Connor) writes: > >I am seeking advice from folks in the community about how to best >upgrade my AT clone to a 386. I want to start a news distribution >service, and hacker haven in the Boston Area. > >Here's what it currently looks like. > > Wyse 286 (10 mhz) (640k) > Intel Above board (4 meg) > 4 port Digiboard serial card on COM2: > 1 port serial card on COM1: > 40 meg hard drive (primary) > 20 meg hard drive (secondary) > >I would like to turn this into a 386 box. >If you have any other ideas or advice, please feel free to give >them... ("I am as you humans say, 'all ears'"). > One option that I'm looking at is a 386 AT mother board. There seem to be several available (Intel, Mini 386 from Taiwan, etc). These typically have either 32 bit slots for the 32 bit memory or room for memory on board. For example the Intel mother board has .5MB on board with two slots, 2 and 8 MB cards are available (although the 8's are very pricey). The Mini 386 has no 32 bit slots but allows 1/2/4/8 MB on board by using 4/8 256kb or 4/8 1MB SIM Strips. These machines are very fast, (Intel 16Mhz 1 wait state, Mini 386 16Mhz 0 wait states) when accessing the 32 bit memory. But they are typically much slower accessing 16bit memory. So if you're running Unix you don't want to use anything but 32 bit. As an example a 32 bit read on the Intel mother board will take either 187.5 or 312.5 nano-seconds depending on whether the data is coming from a "busy" bank. This is compared to a 32 bit read from 8 bit memory taking 1000 nano seconds, and from 16 bit memory taking 3125 nano seconds (this is from the Intel manual, personally I'm convinced that it's probably 1000 for 16 bit and 3125 for 8 bit, but then who am I to argue :-) ). In theory you should be able to take any 286 AT and simply replace the mother board using all of your existing hardware and software. If you wish to run Unix then you will want additional 32bit memory (2MB minimum). Guestimates on cost: Intel about $1400 for motherboard, $800 for 2MB memory card. Mini 386 about $1020 for a 1MB board. Upgrade to 2MB is inexpensive ($200), to 4 or 8MB is quite expensive ($1200/$2400, if you can get the 1MB SIM's). I'm currently using the Intel board in a Bell Tech machine at work. We are fairly happy with it using Microport System V/386. It certainly run's rings around my little Callan ( 10Mhz 68010 ) here at home. The Mini 386 would probably be a little faster due to 0 wait state for interleaved memory access. We just did some tests tonight on loading down a dumb serial card (vintage 1983 Hostess 8 port card). Basically terminal I/O for a couple of terminals at 19.2 was fine. One trailblazer at 19.2 was fine as long as nothing much else was happening (on the other serial ports). I don't think there would be any problem with up to four 2400 uucp links although I won't be able to test that until next week. I don't know yet where the problems with multiple high speed uucp links lies. It's probably lost characters due to interrupt loading, but could be lack of clists to put the incoming data. With two 9600 and one 2400 uucp links going there was not a whole lot of processor power left :-) If it is simply processor loading I'm not to sure that it might be curable by a better driver design. One test showed that we could cause an incoming uucp link at 9600 to loose characters simply by cat'ing a small file to a screen (on a lower port number). That is simply bad design, a driver should always give priority to incoming data if it can. If you are going to really load down the system with serial I/O you should look at a smart card. We've got the Bell Tech ICC card and after some initial teething problems with the modem control software which they have almost got fixed (the remaining problems are fairly obscure for low speed links, with the only serious problem being supporting high speed modems). They are aware of the problems and have promised a to get a working version in short order. I like this card and it now works very well for terminals and low speed modems (up to 2400 bps tested). Given their low cost (about 50% more on a per port basis than most dumb cards) they are a pretty good deal. -- {ihnp4!alberta!ubc-vision,uunet}!van-bc!Stuart.Lynne Vancouver,BC,604-937-7532