[K12OSN] Proposal for Middle School Computer Lab

James P. Kinney III jkinney at localnetsolutions.com
Tue Jul 29 17:53:22 UTC 2008

On Tue, 2008-07-29 at 13:10 -0400, Stephen Crampton wrote:
> Any comments on the following?

Yep! Check inline.
> ------------------------------
> ---------------------------------------------------------------------------
> My preference would be to set up my classroom as a thin-client system.
> With the hardware I discuss below, we could have a "cutting edge"
> computer lab that would be ideal for the educational needs of our
> students.
> Before you read further, would you please peruse the following case
> study:  http://www.k12ltsp.org/rhs_casestudy.html
> I think we could set up a Linux lab for considerably less money than
> described in the case study:
> 1. The case study cites 2002 prices; all of the equipment should be
> much cheaper today.
> 2. We should look to local businesses and parents to donate equipment.
> 3. With a down-turned economy, there has got to be an excess of
> computer equipment out there from down-sized businesses, etc.  We may
> be able to get new or gently used equipment at big discounts.
Used business-class desktop make good thin client (especially if the
hard drives can be removed) or use them as stand-alone linux desktops
with remote /home storage.
> Note that the case study includes Mac, Linux, and Windows.  For my
> lab, I would recommend having only Linux to start with.  In this case,
> we would have $0 licensing costs.

Avoid putting in the proprietary OS stuff at all costs. It's like a
virus/fungus/mold. Once it takes root, it spreads and wipes out all the
other stuff. Mac has a place (in the video lab) and windows does as well
(playing games) but a Linux-only initial setup make later expansion
easier to justify.
> I like the thin-client paradigm for the following reasons:
> 1. It is easy to maintain; only one machine (the server) needs to be
> configured and updated.  By the way, the school's network will
> directly interact only with the server, so security and other issues
> should be easy to resolve.
> 2. It is easy to control the classroom.  In particular, from the
> server I can see what everyone is doing, send messages to them, take
> control of their computers to help them with issues, and blank the
> screens when I want everyone's attention.  Moreover, I can display
> student work on an LCD projector so that students can evaluate each
> other's work.

Good plan. fl_TeacherTool is excellent and highly recommended.
> My syllabus for the year would include the following topics, all of
> which the lab would be ideal for:
>    -programming using Logo and Alice
>    -using spreadsheets to organize data, perform computations, and
> display graphs
>    -3D animation using Blender
The big server can be used after hours for heavy rendering tasks.
>    -digital-image manipulation using G.I.M.P. (a Photoshop clone)
>    -space exploration using Celestia and other planetarium software

Celestia requires hardware accelerated 3D graphics. If you have that
hardware, great!. If not, it is too slow to be useable.
>    -web-page creation
>    -podcasts and webcasts
>    -other lessons utilizing the wealth of software included with
> Edubuntu (http://www.edubuntu.org/UsingEdubuntu).
> I'd like to tie in my topics with other teachers, especially math and
> science teachers, so that topics learned in other classes can be
> explored further in my lab using constructivist learning techniques.

The wealth of science tools in Linux are astounding. The challenge will
be to narrow them down to the ones suitable for middle school. There are
many that are "research-grade" available and they may be daunting.
> Regarding the "client" machines (the machines the students actually
> use), I think we should have 27 of them (2 spares).  Here are three
> options:
> 1. Diskless, fanless machines similar to these:  5 HP clients for
> $750.  These machines save a lot of space, heat, energy, and noise.
> Fans actually make a lot of noise, especially when you have 27 of
> them.  I really like the idea of having LCD screens to replace the CRT
> monitors.  The ones used in the case study can be gotten for $107
> (http://www.starsurplus.com/viewitem.lasso?i=LCD1550V-B).  We might be
> able to get a better price buying 28 of them (includes one for the
> server).  They save a lot of space, heat, and energy.  In addition,
> they are better for the students' eyes.  We might also be able to get
> a vendor to throw in some free keyboards and mice.  Total price <=
> $7,000.

Fanless is best. However, be prepared to do some tweaking to get a happy
setup with 3D hardware accelerated graphics. None of the available thin
clients I've seen yet have NVidia graphics (really good hardware
accelerated support with the NVidia drivers).

Check this little box out:


I've used their little brother and been very happy. The new one has 3D
graphics and more RAM and horsepower. It will still need some tweaking
but being able to bolt to the back of an LCD screen has many, many
> 2. Laptops with hard drives removed give you a "thin client,"
> keyboard, mouse, and LCD monitor in one.  It's possible that we could
> get business donations for these.
Old laptops make good r However, any failure puts the whole thing out of
commission. Beware: some laptops won't boot without a hard drive and
some won't boot once the battery fails. Grr.
> 3. We could use the machines in the room, plus another 14 or so
> similar machines, so that each student has access to a computer.  The
> biggest challenge with this is fitting all of the machines and
> students into the space in such a way that it is a good learning
> environment.  The current machines are noisy, hot, and energy
> inefficient.  Replacing the CRT monitors with LCD monitors would help
> a lot.

Ditching the CRT's is a space, cooling and vision saver!
> Because I would like to have the students do 3D animation using
> Blender and video editing, we need as powerful a server as we can get.
> The minimum recommended memory is 128 MB per client x 25 = 3.2 GB
> memory.  To permit animation and video, I would like at least 6 GB of
> memory.
Correction on the memory calculation: 512MB for the server itself, plus
128 per user.
Yes, you can reserve smaller amounts for the server but you will start
getting some slow down. As soon as the server _needs_ to use swap space,
the system is sunk. It will use swap early but for non-critical stuff.

The animation and video stuff uses RAM but is mainly CPU intensive. Fast
cpu and multi-core, multi-chip is best. A dual-chip, dual-core 2.4 GHz
Opteron with 16GB of RAM will do fine as a server for 100 simultaneous
thin clients. But add in streaming video or flash think: United
Streaming) and that supportable client count drops to 50 or less.
> Here is a sample server:  Dell PowerEdge™ SC1430  I'm attaching a
> quote for $3,500 for the server.  I assume that we can get a better
> price as a public school.  For the quote, I chose a RAID5 controller
> with three disks.  This speeds up disk access and protects us against
> disk failure.  If one disk fails, the system still works until we
> replace the disk.  If we want to stick with a single disk drive, we
> can save a few hundred dollars.  I also chose the maximum memory of 8
> GB for the best performance.  We could save a few hundred dollars by
> starting with less memory.
Skip the Raid5. The read speed is the same as Raid1 and the write speed
is slower. Go for a raid1 root partition on a pair of 300GB SATA II
drives and plop in a second pair of 500GB SATA II for a raid 1 /home.
The only way to get better performance is to get hardware Raid which
costs more than the extra drive anyway.
> It's also possible that the school district has a server we could use
> or that we could get a donated server.

Be sure to put the used machine through a rigorous burn-in test. You
credibility is one the line and the server is a central point of
> We need a switch for the 27 computers plus one server.  I would
> recommend a gigabit switch so that there will be enough speed to
> display videos and animations on all of the clients.  We also need
> cabling for all of the computers, including network cabling and power
> cables.  It might be a good idea to put the server on a UPS power
> supply to protect against surges and power outages.

Gig-uplink switches are good. Most thin clients are 100Mb anyway so an
all gig switch is radical overkill. Be aware of bandwidth issues early
and use multiple gig NICs in the server. In my 100-client servers, I
used 4 gig NICs bonded. The bandwidth really only called for 2 until the
video stuff started up, then all 4 were maxed out. You can bond a pair
to one 24-port and another pair to a second 24-port. A 48-port is more
$/port than a pair of 24's.
> We need enough tables for all of the computers.  I'd like to cluster
> the computers into groups of 5-6 students, where each student can see
> all of his or her group members' screens.  If the clients are very
> small, we may want to lock them to the desk to prevent theft.
If you use laptops, they are a theft risk. Tiny thin clients are not.
Once it gets out they don't work at all without the server, nobody wants
them :)

Be aware that is middle school students can _touch_ each other, they
will get very little work done! And they are big! It is often they will
need both room for a keyboarde, a notepad AND and open book and mouse
space all at the same time.
> I need an LCD projector and screen so I can demonstrate how to do
> things on the computer.  The image should be large and bright enough
> so that everyone can see it clearly.  The LCD resolution should be at
> least 1024x768 so that the kids can see the little buttons and
> controls on programs such as Blender.  With the thin-client setup, I
> will be able to display one or more student screens on the projector.
> This may be how we wrap up most classes, by having each student (or
> perhaps each group) show their day's work.  I've attached a sample
> screen shot to this email.

I have an epson and it's great! Be aware that TeacherTool can be used to
share a screen for all to see and it doesn't require additional
> For audio editing and podcasts, we need headphones and microphones for
> the students.  They can be inexpensive ones.

Be sure to check if the mic input works on your clients before you push
ahead on this. 
> For video work, it might be a good idea to get some webcams.  Most
> webcams have microphones built in.  The webcams could be also used for
> creating webcasts.
Webcams are hit or miss on working with Linux. About 1/2 of the usb
stuff I've tested doesn't work at all with Linux. I don't know first
hand if even the working ones will work from a thin client environment.

Hmm. More testing.
> For image editing, I would like to coordinate with the photography
> teacher.  In particular, does he or she have digital cameras for
> student use?  If not, I think it would be a good idea to get 5 or 6
> inexpensive digital cameras, so that each group can have one camera.
Cool idea! It might also be a good idea to look into a drawing tablet as
well. They should work OK as they are seen as a fancy mouse. Again, it
will likely take some tweaking but it'll be worth it. I have an older
serial port Wacom tablet and can't imagine using a mouse for freehand
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James P. Kinney III          
CEO & Director of Engineering 
Local Net Solutions,LLC                           

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