🚀 go-pugleaf

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