Beowulf - Single Board Computers?

[Robert G. Brown]

On Wed, 16 Sep 1998, Walter B. Ligon III wrote:

(In response to Gary Huntresses original posting:-)

> --------
> At one time the GSFC guys and I were planning to build a beowulf from
> laptops - the code name was "lap-dog."  I decided we could use a wireless
> network adapter, put the nodes in a large box and put the box in front of
> a tornado - we would have the first tornado-born parallel computer.  It could
> process data on the structure of the tornado real-time.  There are many
> interesting problems - for example the topology is always changing, and
> nodes are always going offline.  I never could figure out hot to get the
> processors airborn, the little fins from the movie never really worked out
> in practice.  Its alway's something.

:-)

> Anyway, we didn't build lap-dog, instead we built grendel (our first
> beowulf machine).  I still think one could build a rather compact machine
> from laptops with the display removed (or laptop motherboards).  I have
> seen such a thing at a conference, but they were trying to bill it as
> "portable."  Its not - the network cards suck more juice than your average
> battery wants to supply for a long time.

Boy, if it's one thing that being married for twenty years or so has
taught me, it's how to shop:-).  If y'all run out to the grocery store
today, pick up "Computer Shopper" in the big magazine rack.  On page 377
(of September 1998) there is an ad for Siliconrax (www.siliconrax.com).
Or heck, since I just gave you the URL, you can save $4 and just check
out the website.  Oooo, just OODLES of rackmount single board computers,
each one the size of an old ISA full length card (look like they'd plug
into an ISA bus, even)! Even dual PII's on a card (in the paper ad but
couldn't find them on the website)!

The dual PPro that they >>did<< have on the website holds 256 MB of
memory.  I couldn't see how to manage networking from the web page --
the single board computers look like they plug into a bus of some sort
and have 440XX PCI support, so presumably there is some way to add NICs
and/or SCSI (they do have built in PCI/2xIDE interfaces).  And of course
silicontrax sells the chassis, SBC, backplanes, etc.  I have no idea of
their pricing, but hey, gotta leave something for you to do...;-)

I'm sure that they are not alone in this field.  There are other
alternatives that one can build out of stock components.  My favorite,
that I saw first at Linux Expo and that is definitely linux-friendly is
Alta Tech (www.altatech.com).  Their boxes come pre-installed with
Extreme Linux -- gee, a beowulf you can buy over the counter!
Basically, they sell a chassis that can hold 8 standard ATX
motherboards, and will fill it for you with Intel or Alpha motherboards,
hook up their networking for you (FE or Myrinet or whatever you like),
load up EL, and ship it to you ready to run.  Prices are EXTREMELY
reasonable -- I think that the chassis itself retails for around $2K,
which works out to be comparable to the $250 apiece you'd pay for eight
high end ATX towers up front.  Everything put inside is basically market
value, with a smidgeon tacked on for the added value.  Very reasonable.

Dimensions are:

 Built for maximum reliability, and optimal use of floor
 space, the ACS series implements standard PCI technology
 in a fully enclosed system cabinet that measures
 approximately 1.5' W x 2' H x 2' D (4 nodes) and 2.5' x 2' x
 2' for 8 nodes. An integral part of the ACS series is the
 power management system which allows control over the
 power to each processor and power sequencing for reduced
 risk of overloaded circuits. This power management system
 allows for individual node maintenance with no system
 down time, providing many of the benefits of "Hot Swap"
 capability. 

Less than half a cubic meter for up to 16 PII's CPUs (assuming dual) and
if one has real money and can afford quads, 32 Xeons.  Not bad at all --
eight Dell Poweredge 2300's (dual PII) eats around 2 cubic meters plus a
whole bunch of annoying cabling.

If I were to build a beowulf today starting from scratch, I would
without any doubt get at least the chassis from these guys.  This option
preserves total commitment to commodity hardware, which is at the nub of
the Beowulf Way.  The silicontrax type rackmounts and single board
route, while attractive from the point of view of compactness, tends to
be specialized and expensive although I don't doubt that you can get
more into less volume.  Worth it, I'm sure, to folks with very specific
engineering requirements in those degrees of freedom, but not a
cost-effect solution for the masses.

   rgb

Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb@phy.duke.edu