On Thu, Dec 4, 2008 at 9:40 AM, mhampton <[EMAIL PROTECTED]> wrote:
>
> Having taught several classes using Sage, I highly recommend setting
> up a server (or possibly more than one if you have a lot of
> students). I tried setting up one sage instance per machine in a lab
> with macs, and it was a real pain to administer. There are quite a
> few advantages of having a small number of servers:
>
> 1) Remote access. In my experience students really like the option of
> working outside of school, and being able to pick up where they left
> off. Since we don't have a nice license for student copies of
> mathematica, this is one area where students love Sage compared to
> mathematica.
>
> 2) Group work. If you have small groups they have share worksheets if
> they are on the same server. It also makes it easy for students to
> remotely ask questions, i.e. they can share their worksheet with you
> and you can troubleshoot or help from the comfort of your home or
> office :)
>
> 3) Easier to maintain. If you want to upgrade the sage version, its
> much easier with 1-4 servers than a sage copy per machine.
>
> 4) Might be faster than a VM version, although this of course depends
> on hardware.
>
> I run my sage servers off of an aging mac pro (quad core 2.66 GHz with
> 8 GB of RAM) and a couple of linux (AMD quad-core) workstations which
> are also about 2-3 years old. Each of those can handle about 20
> students with no problem. If the load is spread out (i.e. not
> everyone in a lab at the same time) they could probably handle 30-40
> students each.
Hi,
sagenb.org is also run using a quad-core 2.66Ghz 8GB mac pro, but it
is run from a vmware machine running on the mac and that vmware
machine has only 2GB allocated to it. Using a virtual machine has
advantages regarding security -- also the virtual machine makes an
automatic snapshot of its state once per day, and saves the last few
days of snapshots.
Here's the script to run the notebook. Note the aggressive memory and
other limits given by ulimit below.
[EMAIL PROTECTED]:~/sagenb$ more notebook.py
from sage.all import *
server_pool=['[EMAIL PROTECTED]']
notebook('sage_notebook', port=8000, accounts=True, address='sagenb.org',
server_pool = server_pool, ulimit='-u 400 -v 1000000 -t
3600', open_viewer=False, timeout=120, secure=False)
Also, I specifically modify the nb.sobj so that it saves state once per day,
instead of every 6 minutes or so. This is necessary since there are several
thousand users, and saving state can take a noticeable amount of time.
go to the sage_notebook directory (e.g., $HOME/.sage/sage_notebook), then
sage: a = load('nb.sobj')
sage: a.conf()['save_interval'] = 24*3600
sage: a.save()
-- William
>
> One problem is that students tend to leave their worksheets running,
> which starts eating into the RAM available. I should probably use the
> "timeout" option in my notebooks, which would solve that problem.
>
> I email my students the IP address and port, or tell them during
> class, and of course use the secure option, and I haven't had any
> security problems yet. Some of my servers are on a VPN network which
> makes them a little more secure too.
>
> Hope that helps,
> M. Hampton
>
> On Dec 4, 10:59 am, "William Stein" <[EMAIL PROTECTED]> wrote:
>> On Thu, Dec 4, 2008 at 7:50 AM, Luiz Felipe Martins
>>
>> <[EMAIL PROTECTED]> wrote:
>>
>> > Thanks for the response and the tips. I agree. When I saw the notebook
>> > server at work
>> > I thought: wow, this is the way things ought to go. There's a lot of
>> > stuff to digest on the threads you suggested, I'll tell how I'm doing
>> > as I go along.
>>
>> Could you figure out if something very much like sagenb.org would
>> work for you? If so, I can literally just give you a copy of sagenb.org,
>> which is nothing more than a VMware virtual machine running on
>> the desktop in my office using VMware workstation. I can delete all
>> the particular user data from sagenb.org from it, change the password,
>> and just give it to you (or anybody) to use.
>>
>> -- William
>>
>>
>>
>> > BTW, I found the following in the Wiki:
>>
>> >http://wiki.sagemath.org/DanDrake/JustEnoughSageServer
>>
>> > Anybody had any experience with it?
>>
>> > On Thu, Dec 4, 2008 at 10:11 AM, kcrisman <[EMAIL PROTECTED]> wrote:
>>
>> >>> You didn't say if this is a classroom lab (so all of your students will
>> >>> be using
>> >>> Sage at once) or a math computer lab for out-of-class homework (so
>> >>> students
>> >>> will go in at random times, convenient for them). Others can answer your
>> >>> questions more definitively than I but I think their answer will
>> >>> depend on the number of
>> >>> students using Sage at the same time.
>>
>> >> I agree. Marshall, you've done the computer lab situation, right -
>> >> any thoughts?
>>
>> >> The out-of-class-time situation definitely calls for the server, I
>> >> think, because otherwise people have to make that trek to the computer
>> >> lab without any real reason. As long as you have enough memory and
>> >> are able to make sure not too many students use it at once, it should
>> >> work; there are several threads on sage-support about this, e.g.
>> >>http://groups.google.com/group/sage-support/browse_thread/thread/6735...
>> >> or
>> >>http://groups.google.com/group/sage-support/browse_thread/thread/b57c...
>> >> the latter one addressing the possibility of having multiple ports.
>>
>> >>> > 3. Set up a Sage Notebook server. Pros: easy for students to use,
>> >>> > access their work from anywhere in the world. Cons: have no idea how
>> >>> > to do it. (I can get help setting up a web server, that is not the
>> >>> > problem, the question is how to set up Sage and the notebook server.
>> >>> > The web server, and Sage, would be running in a Ubuntu server).
>>
>> >> I agree with David on this one; I think it is the kind of thing that
>> >> is not too hard (Sage is pretty robust, and so is VMWare). It will
>> >> take a little effort to set up - but I think not too much, and once
>> >> our sysadmin got it running he said even I could learn how to reset it
>> >> in case something crashed, which is saying something.
>>
>> >> Good luck! The notebook server aspect is a really nice feature of
>> >> Sage for education, because it makes things so convenient for students
>> >> that they might actually do more than they expect... and that's a good
>> >> thing.
>>
>> >> - kcrisman
>>
>> > --
>> > "The main things which seem to me important on their own account, and
>> > not merely as means to other things, are knowledge, art, instinctive
>> > happiness, and relations of friendship or affection."
>> > -Bertrand Russell
>>
>> > L. Felipe Martins
>> > Department of Mathematics
>> > Cleveland State University
>> > [EMAIL PROTECTED]
>>
>> --
>> William Stein
>> Associate Professor of Mathematics
>> University of Washingtonhttp://wstein.org
> >
>
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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