PDP Power Usage WAS: BBS software for the PDP 11

Doug Ingraham dpi at dustyoldcomputers.com
Mon May 22 10:23:00 CDT 2017

On Fri, May 19, 2017 at 5:18 PM, Ali via cctalk <cctalk at classiccmp.org>

> > ___________________________________
> > The plate on the back of my 11/93 says 345 Watts.  That's about a fifth
> > what your wifes hair dryer draws.  Or slightly more than 3 100 watt
> > light bulbs (which your kids leave on all over the house all the
> > time!!) bill
> >
> > I run a similar PDP-11/83 system 24/7 on a BA23 in a Pedestal stand. It
> > has two 2MB memory boards, an Emulex UC07 connected to two SCSI2SD
> > Cards emulating two RD54s and two RA92s, and a DELQA-T running RSX11M+,
> > DECnet and Johnny Billquist;s TCP/IP and it draws 100-105 watts on my
> > UPS.
> Doesn't seem that bad, I am sure some of my vintage servers w/ the 10-12 FH
> SCSI drives, "tons of RAM, and four PPro chips are pulling somewhere along
> those numbers. I may have to invest in a Kill-a-Watt type device to see for
> sure though.
> -Ali

My PDP-8A with 32k core, RX01 Floppy and an extra serial port card pulls
345 watts.
It would be another 100 if I had not replaced the factory fans with modern
airflow units.  If left on 24/7 this would increase the average power bill
in the US by
about 30 dollars a month.

If you want to run a modern version of a BBS and not have it add
significantly to your
power bill then run it on a modern laptop.  These can pull around 50 watts
when awake
and this would add only a little over $4 to the average power bill in the

For even less power would be to use an Arduino (probably a Due) because
then you are
talking less than 4 watts.  This would be about 35 cents per month.

I wouldn't want to run my Straight 8 24x7.and pay the power bill.

Doug Ingraham
PDP-8 SN 1175

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