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Re: Linux Server
> Hi, Well we have been thinking along the following lines:
>
> a dual PII 350Mhz with 0.5GB RAM, 9GB diska.
You mentioned 20 simultaneous users, each of them runs Netscape,
XEmacs, TeX, etc. With 0.5GB, each will have only 20MB (assuming the
system also eats something). I think you need more. At least 0.75.
I also would prefer at least dual Xeon, or even a 4-way.
(I know that in the past, people could live with less, but these
specifications are the minimal for today's demands).
> a) does the Linux or programs like the window manager, can run "multiple
> copies" economically, i.e. if one users needs sau 20MB for the core of the
> WM, the second user needs much less?, well i am sure that computer
> system experts know what i mean!!!! i cant remember the currect term to
> use for this.
Of course things are shared, but only the instruction segments of the
executables and of the shared libraries.
But the critical amount of memory, at least in the examples you gave,
is in the data/bss. For example, a Netscape process may eat dozens of
megabytes after a few hours. On the other hand, you may wait a few
years till Netscape 5 will be ready; It is going to be very optimal
and will not spend resources.
> b) How important is the internal cache of the CPU? is a PII enough.
While the performance of the processors almost doubles itself
annually, it takes many years for the memory. So the cache is VERY
critical. The only reason why small caches are enough for most of us,
is because we are not 20 people on the same machine. Think how much
cache you would want for yourself (for single user). Now multiply it
by 20, and divide by the number of processors. Since we are misers,
divide it again by 2. This is what you need.
Now a small tip: It is very hard to set up a so heavy machine. Offers
from VA Research and/or Penguin Computing may interest you, although
they may look expensive. Alternatively, if you find somebody else (in
this list?) who already has experience with these powers, order him
to consult you in this project. It's not a play.
--
Eli Marmor