Which hardware?

[Knut Yrvin]

Torsdag 15 juni 2006 19:38, skrev Dan Young:
> > 15 * 128 MB = 1920 MB
> > 1 * 256 MB = 256 MB
> > Sum = 2,1 GB RAM ~ 2 GB RAM (on a server with 15 thin clients)
>
> Uh, so 4GB for the 30+ Simon asked about? 4GB is the minimum for
> this, IMHO.

Yes. My mistake about the 15 clients! Yes, 4 GB is right for 30
client. But it's not a minimum. Why? The key factor is concurrent
users. Statistically there is seldom more than 60% of the clients in
use. When installing 50 thin clients no more than 30-35 of them is
concurrently in use at the most. So 4 GB is sufficient for 50 clients. 

> One more recommendation; think about installing and using prelink to
> speed up application launching. It's supposedly most effective on
> large C++ applications (read: KDE, OpenOffice, Firefox). 30+ clients
> all launching OO Writer at the same time can be interesting. ;-)

The startup time for applications on a thin client server is really
fast. It's faster than on a workstation. We have experienced that it
takes 5-6 seconds to log in and start OpenOffice.org for 30
pupils. 

Further, many of the advantages with prelink is merged in with gcc 3.X 
and gcc 4.0.X. [edu|k]ubuntu Dapper uses GCC 4.0.3. With e.g Qt 4 and 
new KDE 4.0 most of the dirty page swaping is fixed and optimised. But 
that's 6-8 months ahead. 

> Don't know how Ubunteros feel about prelink (it's in universe); it's
> installed by default on Fedora.

There are other areas that could be speeded up. In general and
simplified there four ways to do this. But when using thin client the
two first makes most effect:

1. To choose a more light weight approach, e.g change the windows
   manager. Use iceWM or similar in stead of KDE or GNOME.  

2. To clean up and get rid of unnecessary libraries when starting up
   KDE or GNOME e.g: http://www.osnews.com/story.php?news_id=13039
   Developers work on the startup times in the GNOME and KDE projects.
   This improvements is on it's way. 

3. Do smarter booting of the OS. Look at this presentation by
   Margarita Manterola: 
   http://www.marga.com.ar/~marga/debian/boottime/debconf-boot.pdf
   (Ubuntu has done smart things already with Dapper ...)

4. To better utilise the new features in GCC, and clean up application
   code that is slow or less efficient

Regards 

Knut Yrvin