[K12OSN] An idea about thin-clients with flash cards...etc....can it be done?

Les Mikesell les at futuresource.com
Sat Feb 12 17:08:12 UTC 2005

On Sat, 2005-02-12 at 01:47, David Trask wrote:
>   my idea is to have a local boot option using
> flash memory for the thin/thick clients....or something similar.

You probably should follow this project:
or you'll end up having to spend time at every client again to get
the improvements from the next version of the software.

> Three
> reasons....with my younger students (generally Kindergartners) all they
> need to do is a couple of apps...generally Internet browsing with
> flash-based games...and simple word processing etc.

I think anything from a P300 up with a video card that has decent X
acceleration so the CPU isn't spending all its time moving things on
the screen could run the window manager and at least a few apps locally
to scale up the number of clients a server can handle.  But, it will
take a lot more work and management to set it up to save a fairly
small amount of money on servers.

>   My second reason is
> that sometime when I am away from school for a lengthy period of
> time....(like this week I'll be at Linux World in the LTSP booth)  :-)  I
> worry about...what if....the server goes down...then what will my classes
> do?  (it happened last week....luckily all it took was a reboot and I was
> able to talk someone through turning the server off and on over the
> phone...no big deal, but....it happens every now and then...just freezes
> hard...I couldn't even ssh in...so...)  Having an alternate boot...even of
> a simple OS would at least allow them to access the internet or something.

If you have a 2-NIC topology and your local server dies, you are out of
business anyway.  The only thing you can do is to have a spare ready to
swap in.  For a site with several servers, this shouldn't be a big deal
and you can use it for testing new stuff when it isn't needed,
especially if it has swappable drive carriers so you can plop in
whatever you need in an emergency.  If you have to justify spending for
the spare to someone, remember that you'd be just as dead when the
server breaks with any OS, and in this case you don't pay extra for an
extra copy of the software on your backup box.

If you have a gig backbone and servers configured for one NIC
connections so any client can reach any server (unless your switches
break...) I think there is an easy solution.  I've mentioned this
before and I think someone tried it and didn't succeed but I'd like to
pin down the reason.  I think it should be as simple as setting up
DHCP on all the servers but limiting the range on each to a small
number of non-overlapping addresses.  Then each client will receive
it's configuration from the server that responds the fastest to its
DHCP request.  If a server breaks, reboot the client and it should
connect to one that is still working.  If the concept works you could
probably whip up some scripts to fine tune things based on server
load across the site.  You will still be dependent on your internet
gateway, LDAP server, and home directory server so you should have
spares and a plan prepared in case those break too.   

> Reason #3, and this is a biggie....I've noticed that when my entire lab
> uses Firefox combined with Flash plugin...visiting Flash-based web
> sites....the CPU usage on my server goes through the roof....and because
> it's running from the server...the sites tend to be slow.  If there were
> some way for my to run Firefox and Flash locally from a flash disk or
> something...that'd be "very cool".  Ideas, thoughts, suggestions....can
> this be done?  If so how?  And is anyone doing it?

You should be able to run anything you want as a 'local app' on the
client with installing it or making the clients bootable.  All you need
to do is make the app appear on the NFS-mounted partition it gets
from the server.  Enable the local shell on one of the client VT's
and poke around...  Given an LDAP and remote home directory server
you wouldn't have too much more work to do to make the clients use
authentication and mount the homes too. 

  Les Mikesell
   les at futuresource.com

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