User:Martinlanghoff/XS Article for Linux Pro

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Target: 1500 words


All through the ups and downs of media coverage -- some informed, most not -- the core OLPC team has kept working with abandon on its mission: deliver designed-for-education laptops and FOSS to kids in the developing world. While armchair quarterbackers herald doom and gloom, we are building and shipping laptops at a rate of fifty-five thousand per month. As this issue of Linux Pro goes to press, around 400 thousand laptops have been built, most of them in the hands of kids, and some will be travelling to their destination. The logistics of delivery are mind-boggling.

The software stack on them? Linux and Sugar.

The laptops -- known as "XO" in reference to the logo emblazoned on them -- are being deployed mainly in small and medium sized rural schools, and the software on them provides amazing collaboration tools that are independant from any external infrastructure. Once the power supply is sorted -- we help with some interesting tools[url] -- you have a self-organising set of laptops.

But past their independent streak, these are machines with vey limited storage and cpu power, and being personal machines they are often off or out of reach. Many powerful educational tools and services for the laptops need to reside on a machine that is more powerful and is on 24/7 (or at least whenever power is available!).

And we call that machine the school server.

Too sexy

The "School Server" (aka XS) is a custom Fedora spin, a specialy configured Fedora that can run either on the XO hardware (with an externally attached HD for storage) for a small school, or on low-to-midrange OTS servers targetted for embedded systems. This is good: our custom spin is much simpler than the one running on the laptop; and is also bad: the XS gets a lot less attention than the sexy XO.

In my view this is a sad state of affairs. Lowly, simple and grey as it may seem, it is the XS that can unleash the XOs in a school, providing internet access (where possible), content and asynchronous collaboration tools. The XS provides an easy way to make a difference for the millions that need it the most.

in a box: [[ John 'Wad' Watlington, our HW architect, does have plans for a very advanced and resilient low-power, no fans hardware design that is resistant to dust, humidity, earthquakes, power spikes and brownouts. But his focus is right now on polishing the XO-1 design, and bringing the ambitious XO-2 hardware design - expected in 2010 - to fruition. It is a huge job for the HW team. OTS hardware mostly suited for the XS role already exists in the market, so it is one less thing to worry about. ]]

Sidebar: add XOs, stirr, and watch the magic happen

Talk a bit about the constructivist approach, hole in the wall

Sidebar: G1G1

Around August 2008 we are planning to reopen our Give One Get One (G1G1) plan. It is a way to get your hands on an XO laptop for you or your kids, while simultaneously donating one to a child in the developing world.

The first G1G1 programme funded XX laptops for YY. Unfortunately, the logistics of delivery to donors were not perfect, and some donors had to wait a very long time to receive their laptops. We are extremely sorry, and thankful of their neverending patience. This relaunch of G1G1 is being carried out with a lot of care to avoid similar issues - do let us know if you have any problems.

Part of the first G1G1 recipients have gotten together into an impressive volunteer support team. If you have a G1G1 machine, or are planning on gettting one, consider joining them at [url].

Developers working on the laptop or server software can also enrol in the developers programme, where you can request sample equipment to test your software. A lot of software can be developed and tested on virtual machines, but for some stuff, there is nothing like the actual equipment.

Bring in the magic

Good quality infrastructure services blend in the background -- end users never hear of them, and might not even be conscious of the existence of the service. A bit like the air we breathe, it gets noticed by its absence.

A lot of the services the XS provides fall in this category -- offering DHCP leases, providing NAT'ted access to the Internet/WAN, DNS services, strong HTTP proxying, etc. This is the bread-and-butter for Linux systems, that machine hiding under a desk that holds the network together and requires almost no maintenance, but we do have some special requirements that make things... interesting.

We have a very tight memory budget -- this machine has to do everything, and in some cases with as little 256MB RAM, so running daemons must be frugal. For example, BIND and DHCPd must make way for more efficient replacements (dnsmasq and djbdns are some of the candidates).

And every single service must be resilient -- in the field there is no such thing as a normal shutdown as power is usually unreliable an

automagic services

proxies and challenges

power off and resiliency

Meet your server

about the face of the XS - wikislice, moodle (offline moodle), mediakiwi, etc.

The Zen of configuration

config plangs

Wizzy, Woffle

offline browsers

On the hardware track

talk about OTS vs OLPC built

Working on Location


Compatibility with the XO, network presence services - ejabberd Gadget, Cerebro etc.

Tinkerer's time