Ouch! It sounds like your school needs a tweaking of expectations (and
some better teacher training!)
A thin client with 512MB RAM is a seriously "hot" machine. The thin
client process just doesn't need that much horsepower on the client.
Where you are getting CLOBBERED is on the server end. Video
decompression is a real CPU intensive process. So 20 students trying to
watch youtube on a 2 GHz single-core Xeon will simple be a miserable
experience. Consider this: A base platform for stand-alone PC with
adequate ability to play youtube and other compressed video formats is a
300MHz PC. That speed will be choppy and halting. At 500MHz youtube
becomes mostly smooth for a cached video. To replicate this playback
ability for 20 simultaneous users on a single server requires
500MHz X 20 users plus 1.5 users for the server = 10.75 GHz
Oops! That hardware is not available so we have to look at multiple CPU
with multiple cores. A 2 CPU, dual core running at 2.6 GHz is about the
minimum needed for this process to work at the server. That is a pretty
beefy machine. Now add in the needed 512MB RAM for the server plus an
additional 70MB per client which puts things right at the 2GB you have
installed.
Now you still have to pump uncompressed video down the network pipe to
the client. So a little, cheap 10/100 Mb switch is just going to fall
over and choke. You will need a 1Gb uplink to the server. A 200x300
pixel video will _eat_ 14.4 Mb per second. The maximum data you can
shove over a 1 Gb line is 730Mbps (ethernet overhead eats the rest) so
in theory a 1 Gb line will support 50 youtube videos.
This next part is the toughest part. Teachers really need help
understanding the difference between passive educational experiences and
active ones. Many teachers are using the passive ones as a form of
electronic babysitting. The teachers today are pounded by sales pitches
to buy software package A and hassled to use the latest Web 2.0 methods
(gag!) without anyone having taken the time to see whether it is more
like watching TV or writing a novel.
**(Note: I'm not blaming the teachers for this situation. We all know
they have no time to do this analysis. I blame the administration,
vendors and media for pushing piles of horrid ideas into policy.
Disclaimer: I am a vendor of Linux thin client systems and support)**
OK. I'm off my soapbox for the moment :-)
Audio and video are really two seriously hard processes to run on the
thin client environment. Most of the audio and video stuff the teachers
are trying to use are all proprietary, closed-source format so the basic
use tools don't ship with the Linux stuff because of license issues.
And then some formats like MP3 and WMV can't be played "legally" on a
Linux machine without buying a license for every client and server. It's
a racket that makes my blood boil.
As for the Mac machines, be sure to compare what you _can_ do on the
Linux thin clients and how effective a teaching tool it is compared to
the cost of Mac hardware and software. Be sure to remind everyone that
the software the students use today will be ancient history in a year or
so and will have to be continually upgraded to stay current. Linux
upgrades are $0. Linux disks can be copied LEGALLY and given away
LEGALLY. There is no cost associated with tracking and proving license
purchase with Linux tools.
I'm a strong advocate of putting the multimedia video stuff on hold
unless it is created by the students! That _is_ a good way to use the
Mac tools (as the Linux stuff is not quite ready as I am soundly
reminded by my professional video friend and colleague).
I designed and built a 7-school LTSP setup that had an average of 100
clients per server. Video playback was NOT an option in the design. But
the ability to do some flash sites, OpenOffice and tons of web searching
and creating web pages and email more than made up for it from what I
was told. The clients all had 128MB RAM and 400MHz cpus. Of course, now
they want the same capabilities as the full desktop environment on
hardware with 1/4th capability.
Cool. I like a challenge and I am pretty close to having that problem
solved with a $450 chubby-client (built-in hardware video decoding).
It's less than a new desktop is installed (software and labor are much
higher with the desktop - with these clients it's plug and go) and there
are no moving parts like fans and hard drives to make noise or wear out.
The machines being given away need to be handled as having the ability
to research on the Internet and do homework. They can't be game
machines. They can be built with a bazillion Linux based games and can
also play web hosted flash games with no problems. Just be sure to avoid
the 3D games as most of the "muffin stumps" will not have 3D video
hardware and the play will be beyond horrid (think 10 seconds per
frame!). Oh, yeah. Always include the grand fun, time wasting game
Frozen Bubble. It's loads of fun and actually has some physics hidden in
it :-) It also has an annoyingly catchy sound track!
The tiny clients I take for trade show demos have a paltry 200Mhz CPU
and 128MB RAM. That is the absolute bottom end and they will play
youtube video as it's done of the server side. At 200MHz the X server on
the client is the slow point. Arcade-style games like Tux Math are very
playable but will never speed up much during play. But these machines
are ideal for basic classroom use to search the web, write stuff, create
presentations with and use the built-in edu games. And they are very,
very low cost. $120 and it will bolt to the back of an LCD monitor so it
takes up no desktop space. So some planing to have a series of basic
clients plus a few beefier ones in each setting works well for several
schools I know of.
Hang in there. This stuff does work and it works well. But a Yugo is NOT
a Ferrari. If the school wants a Ferrari, they have to plonk down the
cash! OK, so a server pile that can provide video for every student
simultaneously is not as costly as a Ferrari but I think it will do more
good than a fleet of Ferrari's will. :-)
Check out your local Linux Users Groups for local help as well:
http://www.lugod.org/
http://www.sf-lug.org/
http://www.balug.org/
Linux users are always (almost!) helpfull. Also be sure to be on the
K12LTSP mailing list:
http://www.redhat.com/mailman/listinfo/k12osn
On Sun, 2008-06-01 at 08:44 -0700, Christian Einfeldt wrote:
hi
I am following this thread with keen interest, because I am a
volunteer level one sys admin for a public middle school in San
Francisco, California. We are running an edubuntu lab with 23 thin
clients with some moderate level of success, but we are actually
giving up on thin clients and sub-512 MB RAM boxes, sadly.
Our problem is that we are seeing that we are experiencing negative
branding with Linux when we use machines below 512 MB of RAM. Even
though 80% of the kids in this school qualify for free school lunches
(meaning that their families are _really_ poor), these kids have been
exposed to computers that will play computer games and will run video
and audio, and they expect computers to at least play YouTube
successfully. Furthermore, the teachers have told us that they would
like to be able to play YouTube across the network, which is something
that we have not yet been able to achieve with this set up.
Our server is newly purchased through the California Microsoft
Anti-trust settlement. Yes, Microsoft paid for 4 high end machines
for us!! See this link for the details:
http://linux.slashdot.org/article.pl?sid=07/10/11/1446254
The server is a dual-core machine with 2 GB of RAM. It's running
Feisty Edubuntu, simply because it was configured almost one year ago,
and of course Gutsy was not out then. We have never been able to get
video or audio running over this network. Now admittedly, part of the
problem might be that I am a simple end user who has just adopted this
school and I decided that I would do whatever I could to organize our
local LUG to get this network running. Unfortunately, we have never
had a Linux geek with deep knowledge to donate a weekend to getting
sound and audio running across the network. As a result, the kids and
teachers use the Linux lab for doing research on Wikipedia etc., but
there is the general feeling that the Linux lab is too feeble to be a
"real" lab.
Contrast this with a mobile Mac lab that was donated to the school
with 15 notebook computers. Those computers are "real" computers in
the eyes of the teachers and kids. The kids compose music on Garage
Band, and are able to play music and watch video. Not so with our
Linux lab, sadly.
So we are in the process of attempting to move from a thin-client lab
to a hybrid lab, in which some form of lightweight distro such as
Xubuntu running on local machines. The server will only serve up
accounts and files; the actual apps will run locally on the clients.
We are hoping that this will permit us to run OpenOffice.org (OOo) and
YouTube across the network so that we can compete on a feature basis
with the Mac lab.
The one thing that we have in our favor is that the Mac lab has only
15 notebooks, and so it is not possible for each kid to have their own
boxes. At least the Linux lab permits the teachers to bring the kids
in as a whole class and have each individual student do research on
their own terminal. Also, we have two media-ready boxes that
Microsoft kindly was forced to pay for as a result of the anti-trust
settlement linked above, and so if the kids need to see video, they
can do so there.
We have also been giving our computers to kids to take home, as it is
our goal to see that every kid can have a computer at home regardless
of family income. Some of our machines have had P4s with 256 MB of
RAM, and those machines have been sort of fairly well received. But
even those machines are viewed as not being able to do video and we
are also having problems with the fact that the kids' exposure to the
Mac notebooks has raised their expectations of what a "real" computer
can do. The machines with less than 1 ghz chips have generally been
the subject of complaints that the machines are "slow".
Now perhaps we need to do some work on managing these kids'
expectations better. But it seems to sadly be the case that machines
that are not capable of running video and editing music etc are viewed
by even these really poor kids as "muffin stumps". By "muffin stumps"
I am referring to the famous Seinfeld episode in which the characters
decide that they are going to try to help NYC's homeless by collecting
the muffin stumps from coffee shops. Most people eat only the tops of
muffins, leaving the "stumps" behind. The Seinfeld gang tried to
collect those muffin stumps and give them to the homeless, but the
homeless rejected them. We are experiencing similar issues with most
of our sub P4 machines. Sad but true. And telling the kids that the
machines are "good enough" is viewed with some skepticism, especially
contrast with those Mac notebooks. Of course, they all understand
that no one is giving out Mac notebooks to the kids, and so there is
some limited measure of gratitude. But it is still the case that
Linux is sadly being seen as "The Poor Man's Machine", whereas the
Macs are seen as "real computers".
We are trying to change our "marketing" of donating the sub-P4s by
telling the families that these sub-P4 boxes are temporary "email"
machines that are designed only for basic letter writing and
Wikipedia-type research, and that those machines are just there to
hold them over until we can get "real" computers to them later.
All of this breaks my heart, and I am very much interested in hearing
success stories with machines that have only 256 MB of RAM and sub-1
ghz chips.
see you
---
Christian Einfeldt,
Producer, The Digital Tipping Point
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