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Low power computing

The purpose of this document is to explore ways for the Tester family to lower its electricity bill by cutting the power used by its many (ten or more) computers.

General ideas

  1. Reduce the number of computers and hard disks. Consolidate two or more computers into one new (and more powerful) computer. And/or, consolidate two or more hard disks into one with newer and more spacious disks.
  2. Switch some hosts to low-power Via mini-itx systems, or Soekris boxes.
  3. Replace some hosts with appliance-like devices e.g NAS.

Specific systems


The 5 hard disks in Mars are drawing approx 37.5W when idle. The K6-III 400Mhz processor, while not low-power, only draws a moderate amount of power (10-20W). The file-server aspect of mars could be replaced with a NAS or Cluster filesystem, then the remaining services could be run from a low-power Via mini-itx system.


The Pentium-MMX PC that currently hosts Baal could quite easily be replaced by a small Soekris box, most likely a single net4801 with a 2.5" hard disk. With three ethernet interfaces on board, it could totally replace the current PC. The drop from 192MB to 128MB of RAM should not cause a problem. Baal currently uses only about half of that, even with quite a few network daemons running e.g Apache, Jabber, NTP, Postfix, Samba, DHCP, Icecast, etc.


The Sempron64 in Buster could draw a good amount of power. Perhaps as much as 75-80W.


With an Athlon 750MHz, Taliesin is most likely drawing a good bit of power (35-40W) just for its processor.

Taliesin would be a good candidate for migrating to a lower power mini-ITX system.


The 266MHz K6-2 processor on Zoe likely draws very little power, but its two hard drives might draw a good amount.


Rhun is a teenaged Sun SparcStation LX. It has survived quite a few power dips in the last year or two. It was three hours short of a year's uptime when the power went out in early february 2006. I would be surprised if it's drawing more than 10W. And if it did, it would be because of the disk drive. You'd save more electricity by turning off the front light at night.


I really can't see Scott giving up anything on his machine. If anything, it will continue to grow in resource usage. However, upgrading to a single large disk drive might help, as might an Athlon64 with power saving features enabled. He only needs ‘full power’ when runnng games or other taxing applications. The rest of the time, it could shift down to a low power mode.


Glenn's probably in the same boat as Scott. I don't see him being willing or able to change his machine much.


Mum could perhaps switch to a Via mini-itx system. Apart from Seti@Home, I don't think she needs much processing power. Just lots of USB ports.


I‘m also in roughly the same boat as Scott and Glenn. But at least I don’t run saavik while I sleep.


To sumarise:

  1. Replace baal with a Soekris net4801 box with a 2.5" hard disk.
  2. Replace taliesin and zoe with a single mini-itx system with a pair of large disks for RAID-1 storage.
  3. Buy new, larger hard disks for desktops with more than one disk.

Taliesin and Zoe

If I could get say, two 250G disks in a RAID-1 (mirroring) arrangement into an upgraded Taliesin with a Via mini-ITX system, then I could do away with Zoe. I could even run Saavik diskless. I've had my home directory on Zoe since my hard disk failure at the beginning of 2005, and have no complaints.

This would replace an Athlon 750 and K6-2 266 with a low-power Via Eden (fanless!) or C3 (small fan) processor. It would also reduce five hard disks down to two.