comparison

[Ray Garza]

On Thursday 31 May 2007 11:39:03 am Gavin McCullagh wrote:
> Hi,
>
> I don't know much about K12LTSP.  What version of LTSP does it use?
> Edubuntu uses LTSP v5 which may be the difference in some of these.
>
> The older LTSP (as I understand it) uses XDMCP straight across the network,
> whereas v5 uses ldm running locally to start an ssh tunnel to the server.
> This tunnel might have an effect on application responsiveness.
>
> Is local device support (usb keys, digital cameras) work on K12LTSP thin
> clients?
>
Yes, it has local device support. K12LTSP 6.0 uses FC6 and LTSP 4.2. The next 
version will have LTSP 5 integrated such Edubuntu.

> On Thu, 31 May 2007, Ray Garza wrote:
> > Booting to the logon screen is about the same.
> > -- Edubuntu: 1 minute and 33 seconds
> > -- K12LTSP: 1 minute and 42 seconds
>
> That's interesting.  Edubuntu is sometimes very slow to boot on thin
> clients but seems not to be here..
>
> > Going from the Logon screen to the Desktop, K12 is a lot faster.
> > -- Edubuntu: 17s
> > -- K12LTSP: 6s
>
> Interesting.  If you turn off LOCALDEV and SOUND on a thin client (just for
> the sake of interest), does this change much?
>
It could be but since I booted from a floppy I did hear a lot of floppy 
accesses. I got a nother PC (thats a Celeton 1.4 GHz) that can boot from the 
NIC and see if there is any difference.

> > Playing Tux Type w/sound is a lot faster on the K12 system
> > -- Edubuntu system: Tux Type was very slow even at its Highest level
> > (Commander w/short words)
> > -- K12LTSP system: Tux Type played just fine
>
> Possibly due to the tunnel.
>
I'm gonna try that 1.4 Ghz Celeron PC and see if that makes any difference.

> > Another thing that I noticed is that I can't (or couldn't figure out)
> > change the logon screen on the client PC. On the K12 system I would goto
> > System-->Administrator-->Logon Window and make the changes there but it
> > doesn't work on Edbuntu.
>
> This is the difference between ldm and xdmcp.  You need to modify some
> settings in /opt/ltsp/i386/usr/share/ldm/themes/ to change the thin client
> login screen in edubuntu.
>
Ok, thanks, I'll poke around with that.

> > The Dell Optiplex 620 works fine under Edbuntu. Sound works on the
> > Applications that have sound and Tux Type or Tux Math work fine. Maybe
> > I'll use Edbuntu for the lab with the new Dell's and K12 with the older
> > stuff. I would like to run both with one system.
>
> The ssh encryption adds a CPU load to the thin client (and the server).
> This may be part of the problem here if your more powerful thin clients
> aren't bothered.
>
> > Any comments? Anthing I can do to get Tux Type and Math to run at it's
> > normal level? I imagine that if I switch to NIC that can boot off the
> > Network some of the sluggishness will go away.
>
> Various people have suggested patches to openssh to add a null cipher, ie
> to not encrypt data in transit.  The guys at PSC provide a patch:
>
> http://www.psc.edu/networking/projects/hpn-ssh/
>
I could try that but it'll be next week before I can get to it.

My overall impression of Edbuntu is good. I really like getting basic sound to 
work with out a lot of hassle. The rest is just a learning curve that I have 
to go through.

Ray