[Server-devel] OLPC News (2008-05-26) - Tech Team

[Andy Rabagliati]

(Copying server-devel)

On Tue, 27 May 2008, C. Scott Ananian wrote:

> On 5/27/08, Andy Rabagliati <andyr at wizzy.com> wrote:
> > > ---------- Forwarded message ----------
> >  > From: Kim Quirk <kim at laptop.org>
> >  > Subject: OLPC News (2008-05-26) - Tech Team
> >  > Scott Ananian:
> >  > * Will be working on a trial integration of Whizzy Digital Courier
> >  > (http://en.wikipedia.org/wiki/Wizzy_Digital_Courier ); let me know if
> >  > you want to help.
> >
> >   I am in Nigeria at the moment, in Abuja, doing an installation for a
> >   University coming on line in July.

Have been quite busy lately, without great internet access .. apologies
for the lateness of the reply.

> >   However, I have made a lot of progress on moving my Email / web scoop
> >   solution from CentOS to Ubuntu Hardy, and making it live nicer with
> >   a package system.
> >
> >   Let me know what you are trying to do and I will see what I can do
> >   to help.
> 
> Well, the OLPC software stack is Fedora-based, so the CentOS packaging
> is more relevant. =)

Yes, the packaging is more relevant, but my redhat install definitely
'took over' the installation process - with much of the configuration
happening on boot after the initial install.

I have made it play nicer with an existing install, and I think it would
be better to re-port what I have done so far back to Redhat.
Configuration now happens when it is supposed to - on package install -
and currently does it using debconf and its database.

> I'm going to be taking a closer look at wizzy-06Aug2006.iso today (or
> is there something more recent?) to figure out how best to integrate
> it.  The major issue at the moment seems to be how to manage a shared
> request queue for disconnected operation.  The walkthrough at
> http://www.wizzydigital.org/community_z_Internet_Manager.html seems a
> little too involved for teachers with no previous internet experience,
> so a more automatic default mechanism for adding sites seems
> worthwhile.

There is nothing much more recent for CentOS, but
ftp://ftp.wizzy.com/pub/wizzy/wizzy-hardy-20Apr2008.iso has Ubuntu Hardy
packages. The relevant package is wizzy-ibox - which has a list of
dependencies to pull in things like exim and dovecot (for email) and
wwwoffle (for web). It also has a set of administration pages - not all
quite finished yet, I am afraid, and the postinstall script creates a
skeleton LDAP directory, used for UUCP routing as well as accounts.

> Here's a quick scenario:
> * In Peru, the teacher and all the kids have XO-1 laptops with minimal
> storage (~500MB)
> * Every school also has a school server with a large hard drive.
> * Presumably, the school server would run (pieces of?) the IBOX
> software and provide a transparent proxy of port 80 for the machines.
> * Once a month the teacher travels to the nearest town with internet
> access, which may be a week away, for "teacher training".
> * The idea is that the teacher should be able to download the latest
> request queue onto a USB stick before they leave, and use the internet
> access in the nearby village to download pages matching the request
> queue onto the USB stick, and then upload the pages into the school
> server.
> * At the moment we're more interested in web than email, but email in
> the same transaction would be a nice plus.  (In Uruguay all the
> schools are being provided with email by the state telco, however, so
> our email mechanism should be optional when the country is already
> supplying it.)
> 
> I assume that the teacher will be using the XO-1 to perform the
> download when they have internet access.  I'm a little worried that we
> might have places with an internet cafe, but no provision for
> networking the XO-1 (no wireless, or the teacher doesn't have the
> appropriate adapter for connecting to a wired ethernet, or the
> internet connected machine has no provision for connection sharing).
> So being able to perform the 'courier' function via a web interface
> from a connected machine with no special software seems desirable as
> well.
> 
> In summary, your Whizzy software looks excellent, and, as is, looks to
> address a large part of our "disconnected internet" use case.  Thanks
> for your work on this!  Perhaps a few tweaks will allow easier
> operation for naive users in Peru's scenario.
> 
> There are probably some longer-term issues involved with integrating
> wwwoffle's web cache with the other web caching solutions discussed at
> http://wiki.laptop.org/go/XS_Server_Services#HTTP_Caching.  We'd also
> like to integrate this caching with central management of school
> library content: Uruguay, for example, has a 'push' scheme for
> updating textbooks/documents/etc on the school server, in addition to
> Whizzy's "pull" scheme.  Long-term we'd like to have a consistent
> story for all of these uses -- although whizzy could be a central
> component in that story.
> 
> Another likely longer-term issue regards schools without school
> servers.  I believe our initial Peru deployments all have school
> servers, but for smaller schools and other deployments, there may not
> be one.  Figuring out how to designate the teacher's XO as a "super
> peer" and having a more decentralized web cache and request queue
> seems to be a harder problem, but one I would hope to be able to solve
> (in part) by moving the wwwoffle/whizzy instance ultimately onto the
> XO, rather than the school server.
>   --scott

To address the web cache aspect only, I described the strategy earlier
on this list, at

http://lists.laptop.org/pipermail/server-devel/2008-February/000221.html

wwwoffle makes this easy for me, as I can just populate the cache by
dropping files in its directory structure. I will have to look at the
other proposed web caches to see if they make it as easy to populate
content from elsewhere. Using the filesystem as the database is great.
If I had to 'update' some index or other as well it might make it more
difficult. I will check out the wiki.

The main enabler for using USB keys is to package all communication as
going over a UUCP transport. UUCP is very simple conceptually,
transferring stdout/stdin to a 'program' over a 'path'.

Wizzy Digital Courier has a web interface and some basic authentication
that allows a person to plug a stick in one end, click, unplug, carry to
the other location, log in, plug in, click. This performs the UUCP
transfer, and wwwoffle scripts and/or exim handles all the web and mail.

On a lighter note, I am at present very close to Galadima School, Abuja,
Nigeria, and will be visiting the OPLC pilot lab there next Monday, and
hopefully also meeting the local chief!

Cheers,   Andy!

http://blog.wizzy.com/