[buug] Clusters

[f.johan.beisser]

On Wed, 4 Sep 2002, Mark Hedges wrote:

> I was wondering myself, do beowulf nodes have to run on
> identitcal machines?  Can a beowulf run on disparate units?
> Would it just bottleneck processing speed to the slowest CPU?

my understanding is that modern beowulf clusters do not need identical
machines anymore. although, it's usually less expensive to have them
identical anyway.

> Does anyone care to explain the difference between parallel
> computing and distributed computing?

sure, i can try.

distributed computing involves breaking a problem down in to small
sections before handing out each section to a given CPU. for example,
distributed.net has a client that grabs sections of a given problem, and
computes results, before handing those sections back to the central
server. it's a good way to handling brute force computational tasks (such
as breaking cryptography..)

parallel computing is more complex. instead of breaking a task down to
smaller bits, you have many parts computed at once. the main focus of this
is that you don't assign a single process to a single node (CPU). that one
process may have n+1* nodes in use at any time.

that's my understanding, at least.

* - n+1 nodes means that you have the base node that's handling most I/O
for that process, +n nodes that are assigned to assist in running the
program.

-------/ f. johan beisser /--------------------------------------+
  http://caustic.org/~jan                      jan at caustic.org
    "John Ashcroft is really just the reanimated corpse
         of J. Edgar Hoover." -- Tim Triche