The Magnet Group computation (simulation?) server: magsim
Note: these pages are largely out of date, superseded by
ETK Computation Server[s] pages.
These pages are intended to introduce the computation server,
magsim.ets.kth.se, and to ``improve the experience'' by
improving your understanding of the system.
They give an introduction to the programs available,
how to use them from your own computer (at work or home)
and the details of the hardware/software system.
A description of the system
A description of how to access the system
by conventional methods (SSH shell, remote X), or
by TightVNC to allow graphical programs to continue after logout.
An introduction to some essential
system commands, which is also of use for many other systems.
Some available applications
for various purposes (simulation, writing, et cetera)
The main advantages of centralising this sort of computation work
are:
- memory is important for many simulations: by concentrating it
and relying on the fact that it is rare for all users to want it
at once, we get either or both of lower cost and higher performance
- when memory runs out, disk-based swap can be useful: by using a dedicated
SCSI disk for swap, the swap speed is vastly increased compared to
normal PCs.
- having multiple processors is not very reasonable for each user, but
(as with the memory) the resources can be concentrated so that all have
access to them in one place: some programs and tasks can take
advantage fo multiple processors to increase the speed considerably
- software installation is simplified, as only one installation is made
then the programs are run remotely
- some licensing schemes for proprietary software might make it cheaper
to have a program on just one computer, even if many users can take advantage
of it at once...
- the server is left on, so non-interactive programs can be "backgrounded"
and the user can log out, leaving long tasks running even if his/her
own computer is to be switched off or logged out, or happens to crash...