Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!rutgers!ames!ucbcad!zen!ucbvax!hplabs!cae780!tektronix!gvgpsa!davew From: davew@gvgpsa.UUCP (David White) Newsgroups: comp.sys.dec Subject: Re: MicroVax II configurations Message-ID: <514@gvgpsa.UUCP> Date: Thu, 6-Aug-87 12:38:05 EDT Article-I.D.: gvgpsa.514 Posted: Thu Aug 6 12:38:05 1987 Date-Received: Sat, 8-Aug-87 12:34:27 EDT References: <269@ddsw1.UUCP> <4803@utah-cs.UUCP> Reply-To: davew@gvgpsa.UUCP (David White) Distribution: na Organization: Grass Valley Group, Inc., Grass Valley, CA Lines: 62 In article <4803@utah-cs.UUCP> cetron@cs.utah.edu.UUCP (Edward J Cetron) writes: >In article <269@ddsw1.UUCP> michael@ddsw1.UUCP (Michael Duebner) writes: >> >>We would like to use the following configuration >> >>MicroVax II BA-123 >> 16 MB of RAM >> 4 RD-54 fixed disk drives >> 4 DHV-11M communications boards Why use 4 DHV's? First, I don't think that you will have room for more than 20 ports on the distribution panel, unless there is an option that allows you to use 9 pin rather than 25 pin connectors. I would recommend using terminal servers for terminal connections since you can put the servers in the areas where the users are and you won't have to run so many cables to your BA123 box. I have also found that the DHV ports tend to get used for other purposes, such as printers, modems, direct 232 links to other computers, emulators, and other such devices. We have 20 ports on our system, and only 5 are used for terminals, with the rest being used for other devices. Hence, most of our terminals get hung off of terminal servers. >> TK-50 tape drive > > 2. The RD54's take a lot of POWER. I think that if you do a power study with your proposed configuration you will find that there is not enough beef in the BA123 power supplies to support that many RD54 devices, especially with the start up power requirements of the RD54's. > > 3. RD54's get HOT.... > > 4. Given the current ba123 cooling system, and power supplies (dual) >DEC only supports three RD53's (or 2 RD54's and one RD53 or ...) and one >TK50 per box. > > 5. personally, I would use two RD54's and the tk50 in the box, and >two RD54's in external boxes with external power supplies.... I agree with this. There is a catch however. > > 6. but then again, I can't remember if you can run the signals out >from the distribution panel of a ba123...if you can, 5 is the best approach. >(doesn't the external boxes require rqdxe's??) To use external RD54's in the BA123, you will have to run them off a second RQDX3 disk controller. The RQDXE is not supported for the BA123 box, as I found out the hard way! You will need a cable from the second RQDX3 to the distribution panel, and then you can plug in your external RD54. To add more than one external RD54, I think that you will have to daisy-chain off the first external box. Actually, having two RQDX3's is not bad since it seems to give better throughput that having 4 devices hanging of off one RQDX3. -- =================================================================== Dave White Grass Valley Group, Inc. P.O. Box 1114 Grass Valley, CA 95945 UUCP: ...!tektronix!gvgpsa!davew PHONE: +1 916 478 3052