Re: [9fans] Plan9 - the next 20 years

[tlaronde@polynum.com]

On Fri, Apr 17, 2009 at 03:15:25PM -0700, ron minnich wrote:
> if you want to look at checkpointing, it's worth going back to look at
> Condor, because they made it really work. There are a few interesting
> issues that you need to get right. You can't make it 50% of the way
> there; that's not useful. You have to hit all the bits -- open /tmp
> files, sockets, all of it. It's easy to get about 90% of it but the
> last bits are a real headache. Nothing that's come along since has
> really done the job (although various efforts claim to, you have to
> read the fine print).

My only knowledge about this area is through papers and books so very
abstract.

But my gut feeling, after reading about Mach or reading A. Tanenbaum
(that I find poor---but he is A. Tanenbaum, I'm only T. Laronde),
is that a cluster is above the OS (a collection of CPUs), but a
NUMA is for the OS an atom, i.e. is below the OS, a kind of
"processor", a single CPU (so NUMA without a strong hardware specifity
is something I don't understand).

In all the mathematical or computer work I have done, defining the
element, the atom (that is the unit I don't have to know or to deal with
what is inside) has always given the best results.

Not related to what you wrote but the impression made by what can be
read about this "cloud computing" in the open sewer:

A NUMA made of totally heterogeneous hardware with users plugging or
unplugging a CPU component at will. Or a "start-up" (end-down) providing
"cloud computing" with as the only means the users' hardware connected
is perhaps a WEB 3.0 or more, a 4th millenium idea etc. but is for me at
best an error, at worst a swindle.
--
Thierry Laronde (Alceste) <tlaronde +AT+ polynum +dot+ com>
                 http://www.kergis.com/
Key fingerprint = 0FF7 E906 FBAF FE95 FD89  250D 52B1 AE95 6006 F40C