[Community-news] OLPC News (2007-03-11)

[Walter Bender]

1. Cambridge: A three-day (36 hour) working session took place at OLPC
headquarters with a subset of launch countries (Argentina, Uruguay,
Brazil, Nigeria and Rwanda), asking the countries to be partners and
critics. An extremely interactive meeting ensued, at times boisterous
and combative, from early morning to late evening with only a few
breaks and minimal sleep. Every topic was touched from firmware to
firm agreements.

2. Cambridge: At a two-day design review with Quanta and Fuse Project
we finalized all ID and mechanical changes and most electrical
changes.

3. A team from the MIT Media Lab spent the day at OLPC presenting
current and potential plans for the XO. A highlight was a presentation
of projects from a class being taught by Henry Holtzman and Ted
Selker.

4. A method for creating 400 different colors of XOs on the back cover
of the laptop was decided: multi-color XO pieces of plastic will be
attached via heat stake to the back cover of the laptop. 20 colors
will be used for the X and the O, creating 400 unique combinations,
enough for each child in a small school to have their own colors.

5. The Red Hat team has generated 60 builds in the last month and a
half—a strenuous pace. Build 299 was released this week. A new stable
build, the first one that will be used by children, will have many
improvements and some new activities: a Tetris-like game, a slide-show
activity, and a preview of the journal.  The firmware team at OLPC was
also been busy preparing release B76, which fixes many of the battery
problems experienced in earlier releases.

The new build contains some new activities and also improvements in
many of the existing activities. The Abiword word processor activity
has had a  number of bug fixes and is the first activity that saves to
the journal when you close it. TamTam has been vastly improved and now
includes a track editor. The web browser is vastly improved: it
properly scales pages, text, and images to our 200dpi display and
includes the Gnash free-software flash viewer.  The news reader
included is also more obviously named.

There are also changes to the Sugar API to support new functionality;
lots of bug fixes and changes have been made to the new mesh view,
which is where network activation now takes place. Also, a splash
screen that takes a child's picture and asks their name is included
with this build.

This build also includes a new Marvell firmware that fixes a few
mesh-related problems; a big step forward. This is in conjunction with
a new kernel that fixes some problems that were showing up under heavy
network traffic will make a big difference in our networking
experience.

We are about to release a new auto update image that will let people
upgrade from version B43 (the last stable release) or B61 (included on
the B2 machines) to B76 which includes important battery charging
fixes that many people have run into.  It also fixes the problem where
the wireless does not show up after a reboot. Please upgrade your
systems
(http://wiki.laptop.org/go/Btest_Boards).

The kernel in this build also contains a software work around for the
problem we were seeing where the touch pad jumped around when you
released your finger.

Many thanks to Dan Williams, Marco Gritti, Richard Smith, Marcelo
Tosatti, John Palmieri, Chris Ball, Tomeu Vizoso, the Abiword team,
the TamTam team, Andres Salomon, and Owen Williams, who worked very
hard on this release.

6. From the community: Build 299 includes the beta release of the
TamTam music editor. TamTam Edit is a page-driven event sequencer
featuring a powerful music generator, a colorful and intuitive
graphical interface to create, modify, and organize notes on five
virtual "tracks," a palette of almost one-hundred sounds, and a
music-construction model that allows virtually limitless variations in
all musical styles.

TamTam Edit joins miniTamTam and TamTam synthLab as the third
component of a complete music and sound creation and collaboration
environment on the XO. A fourth component, consisting of a
collaborative playing and composing tool,
will be forthcoming as soon as the mesh-network APIs stabilize.

TamTam Edit uses about 55–65% of the CPU when running full tilt and
presently occupies about 20MB of RAM. Kudos to Jean Piché, James
Bergstra of the Université de Montréal and Adrian Martin of the
University of Toronto for making this a reality—given the constraints,
this is an engineering feat of no small proportion. Olivier Bélanger
and Nathanael Lécaudé, both of the Université de Montréal have also
contributed an enormous amount of time to create what is turning out
to be a suite of expressive tools we are extremely proud of.

7. Video: Erik Blankinship and Bakhtiar Mikhak from Media Mods have
video capture and playback working within in the Camera Activity. It
will be folded into a build coming soon.

8. Richard prepared a CD that contained a Build 282 set up for QEmu
and the latest Develop Activity from Andrew Clunis (orospaker). SJ
Klein distributed the CDs at the Serious Games conference. Special
thanks to Andrew, who pulled together an easy QEmu install built and
integrated the Develop Activity in to
Build 282.

9. Kernel: In the quest to get a stable kernel ready for our new
stable build, Andres worked with Tom Gleixner to fix the kernel crash
we were seeing; that has since made it upstream (along with a few
other problems that were noticed in hrtimers). There were some
libertas wireless driver changes that went into the kernel, and Andres
enabled some netfilter modules to allow NAT to work. Chris notes that
the dyntick bug that we had been seeing (#954) isn't really fixed, it
is just harder to reproduce. Ah, races are fun.

10. Performance: We've recently focused effort on solving a problem
that costs 30% of the performance of the system when a network
interface is enabled. This is due to a cache snooping issue with USB
that the GX processor has. Mitch Bradley verified that the "uncached
descriptor" workaround for the USB/BTB performance problem nearly
eliminates the CPU performance hit. Andres worked on adding a new
memory zone to the kernel for uncached memory allocations; that work
lives in a separate kernel branch [0]. Marcelo is in the process of
testing it to see whether it actually makes a difference for GX
performance with DMA.

11. Firmware: Mitch Bradley made good progress on suspend/resume on B2
using firmware tests. With the board modified to pull DCONLOAD down
instead of up, Mitch can suspend and resume without losing display
integrity and display interaction continues to work after resume. The
core resume is pretty fast: less than 15mS (not counting the time to
resync the DCON to the video, which add an extra 30mS or so). Mitch
can also access the NAND FLASH and SD after resume but does not have
USB resume working yet.

Mitch started to look into use cases for firmware wireless support,
now that Lilian Walter has released a working firmware wireless driver
and Wifi supplicant. Earlier in the week, Lilian released the first
version of the supplicant and wireless ethernet driver to Mitch.
Lilian also worked on country the country code, channel, and transmit
power information so that the driver will comply with local regulatory
constraints (called IE support.) Lilian currently debugging the ad-hoc
join operation.

12. Touch-pad driver: Zephaniah Hull reports the lack of debounce on
the PT to GS switch has been corrected, and the touch pad continues to
work properly.

-walter
-- 
Walter Bender
One Laptop per Child
http://laptop.org