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Re: Dumb terminals possible with i386 Debian



On  0, Andy <list@firman.us> wrote:
[snip]
> Thin client boxes are attractive since one does not have to deal with
> old hardware, failing memory, flaky video cards, hard drives, etc....
> 
> I want to build a Debian server and be able to serve 50-100 thin clients over
> a 100Mbps LAN.   I can build the server but I am at a loss on how to get a 
> thin client running this way.  
> 
> Anyone doing this with Debian?

Sorry, but you're always gonna need memory and a video card.

So this is the sort of thing you want: A bunch of monitors, keyboards
and mice that look like systems but do not have disks.  Everything is
run on the server.

The way to acheive this with Debian is:

* Set up a root filesystem that boots, starts XDM, using XDMCP to pop
  up a login screen that logs the user in on the server.
* Set up your terminals to network boot from that root filesystem.

That's about it, really.  These boxes need no other services running.
Pretty much all you need is a kernel and X.  Nobody needs to be able
to login on the terminals, not even root.  All logins will be on the
server, and all system maintenance can be done on the server.  Each
box will probably need to be at least a 30MHz 486 with 8Mb RAM.

There are good HOWTOs on this that someone else has posted links to.

It is worth noting that it takes a *beefy* server to run 100 instances
of, say, netscape.  Our computer science department used to have a
bunch of old monochrome X-servers that worked in this way.  When they
installed netscape they found that more than about 30 students using
it caused the server to grind to a muddy, messy halt.

Another option our engineering faculty uses is to have a bunch of PIIs
that are capable of running the applications themselves, but that
mount most of their filesystems off a server.  This decentralises the
processing power requirements, but doesn't sound like what you want.

If you want to keep desktops open between sessions you could probably
hack up a login-like interface to VNC.  It will support multiple users
on the server, and will hold on to sessions between connections.  But
as cool as this is, I don't think its a good idea;  if you have 1000
users and 100 terminals then you now need to be able to keep
1000 instances of the applications open, even if most of them are
swapped to disk, even if they are not being used at the time.  1000
instances of netscape can easily chew 50 Gb of memory, especially with
a java plugin.  You will need lots of memory and a *very* large swap
partition.

Tom
-- 
Tom Cook
Information Technology Services, The University of Adelaide

"The secret of creativity is knowing how to hide your sources."
	- Albert Einstein

Get my GPG public key: https://pinky.its.adelaide.edu.au/~tkcook/tom.cook-at-adelaide.edu.au

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