[Beowulf] Flashmobcomputing

[Donald Becker]

On Mon, 23 Feb 2004, John Hearns wrote:

> I hesitate a bit to send things seen on Slashdot to the list,
> but this is probably relevant:
> 
> http://www.flashmobcomputing.org/

  >> A Flash Mob computer, unlike an ordinary cluster, is temporary and
  >> organized on-the-fly for the purpose of working on a single
  >> problem. Flash Mob I is the first of it's kind.

A bit of hype here.
Flash Mob is a fun demo, but not a new system architecture.  All of the
software is on a live CD, which Yggdrasil pioneered back in 1993, and
it's far from being the first on-the-fly cluster.

One of first public demo of Scyld Beowulf was temporarily converting the
email-reading machines at the ALS conference into a cluster.  We did
that in a few minutes, taking only a few second beyond the amount of
time it took to boot the machines from floppy.  Today there is the
opportunity to use PXE boot, which makes configuration even easier.

A key was the innovative approach of making most of the systems
specialized compute slaves, with only the environment needed to support
the fully-cached running application.  (Note that NFS root sounds like a
likely alternative, but doesn't scale and has a run-time performance
impact.)

> It might be worth a bit of a debate though.
> Given that this cluster will be composed of differing CPUs,
> and conneced together by 100Mbps links will it really have chance
> of getting into the Top 500?
> The bootable CF they are using is a Knoppix variant.

The differing CPUs and full workstation-oriented distribution will
likely pose more a problem than the switched Fast Ethernet.

Unless they make significant modifications, they will run into the
scalability problem that every full-installation system encounters: at
every timestep a few of the machines will be paging, running cron, or
doing something else that slows the machine.  That would be barely
noticed in a workstation environment, but is a major problem with most
cluster jobs.

Still, it sounds like a fun, demystifying demo that introduces people to
scalable computing.

-- 
Donald Becker				becker at scyld.com
Scyld Computing Corporation		http://www.scyld.com
914 Bay Ridge Road, Suite 220		Scyld Beowulf cluster systems
Annapolis MD 21403			410-990-9993

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