OLPC:News

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Laptop News 2008-02-09

1. Embedded controller: Richard Smith found a few more “corner cases” where the the EC side of the command protocol can “wedge.” He also discovered—while looking at the kernel's EC SCI handler—that the “unwedge” workaround only works when the EC is reporting up a single byte. EC command failure does not seem to show up on Richard’s testbed and there have not been many reports from the Joyride users with symptoms that would match this failure mode; therefore, these fixes will not make Update.1—we don’t want to hold up the release for the necessary testing and QA; they should appear in the next release. The current round of EC code appears to be holding up well.

2. Batteries: Field reports of batteries that will not charge continue to trickle in. The symptoms are all identical: during a charge the voltage profile changes in such a way that the EC thinks the battery is fully charged and it marks it as such; but since it only received a few mAh of charger when the XO goes on to battery power is shuts off in a few minutes. Nothing so far indicates that it is a EC software problem, but Richard is not ruling it out until he has had a chance to work with the suspect batteries. A sampling of RMA with these batteries are on their way to Richard for examination and return to the manufacture for deeper analysis.

3. Power usage: Richard continues to gather data and analyze the power consumption of the XO laptop while trying to auto-suspend under “real world” conditions. (Many people have offered to gather data for him.) Based on data gathered in the OLPC offices, laptops don’t stay in auto-suspend while not being actively used: there is a constant stream of wake-ups. This skews the result heavily towards a shorter battery runtime. To get an accurate profile of the actual activity level, these wake-ups need to be eliminated or minimized. The prime suspect is the WLAN: an XO laptop that auto-suspends not in the noisy RF environment of the OLPC offices will stay in suspend until user activity or the low battery wakeup occurs.

Chris Ball provided Richard with some power readings from our newly enhanced power tinderbox running a C2 (mass production) laptop. It allows us to sample the power draw of the various sub-systems while in sleep, something that the olpc-logbat script cannot do. The top auto-suspend power-draw breakdown:

WLAN 734 mW
backlight 362 mW
memory 239 mW
LCD 218 mW
EC 108 mW
other 339 mW
total 2064 mW

The “other” category seems high, but it includes the switching regulator efficiency loss across all categories. A more details audit of these numbers will happen in the future. The good news is that the 2W total matches what olpc-logbat reports as being the average for a 4.5 hour uninterrupted suspend session so measured matches reality. The bad news is that this works out to only about 8.5 hours of battery life with no wakups. To get to greater than 10 hours, we are going to have work out methods of determining when we have been inactive for extended periods and turn off both the LCD and backlight under those conditions. We have timers in the system that will do this under normal non-suspended operation, but auto-suspend currently prevents these timers from ever expiring. For long auto-suspends, the only LCD and backlight power savings we get are from freezing the display and dimming the backlight. Recovering over 500mW in the extended-suspend case would make a big difference in the “no interruptions” test case which is an upper bound. (Note that in “eBook” mode, the backlight is off, providing additional power savings.)

A next step will be to see if the wireless power can be reduced during suspend. Currently the suspend/non-suspend power draw for the WLAN module is the same. When the driver and firmware are mature enough, we will be able to fine-tune the power draw under both conditions.

The EC also has a low-power mode that is not utilized in suspend. More recent requirements of the EC have it doing things that involve watching timers. Refactoring the code such that the EC can sleep and still do its chores will be a pretty invasive change. But as the more low-hanging fruit is picked, turning that 100mW into 1mW will be targeted.

4. School server: John Watlington spent time this week working with a three-server mesh at the OLPC office in Cambridge. Scott Ananian turned the mesh testbed back on and we quickly saw the network become unusable. We are working on registering every laptop in the office to see if that helps. In the meantime, he has setup a school server on a different mesh channel in preparation for next week's learning workshop. It has already been used to show that problems with sharing and inviting friends to join activities experienced around the office are related to the network load, not the presence of a school server.

5. Multi-battery charger: Bitworks has provided Richard and Lilian Walter with the second-round prototypes of the charger PCB with five channels loaded. This lets the firmware development continue. Various discussions with the manufacturer of the DC–DC converter chip have flushed out the causes of higher than expected temperatures; a third round of prototypes should fix these issues. The first test plastic and sheet-metal parts from the fabrication tools have been produced and Gecko has been working with the manufacturer fixing the issues that always arise with new tooling. A full set of parts to assemble some complete units are expected at the end of February.

6. Tech team: As part of the restructuring required to meet new challenges, a technology team has been formed to focus on HW/SW development, testing, support, and systems administration (IT). Over the next week we will define goals, work with the other teams (development and deployment) to understand their needs, and outline a plan for resourcing and meeting those goals.

7. Schedule/testing: Update.1 RC2 (release candidate 2) was made available on Friday (http://download.laptop.org/xo-1/os/candidate/691/jffs2/); it is signed and ready for testing. Please help test this build (See Test_issues and Update.1).

8. SysAdmin/IT: Welcome to Henry Hardy, who joined us this week as OLPC systems administrator.

9. HW/SW Development: This week the first 100 G1G1 users had Build 656 pushed to them automatically. We are only pushing this build to people running Build 649, 650, or 653. Basic information about update streams (and how to unsubscribe your laptop) is available in the wiki (See Update_streams). Expect to see Build 656 pushed more broadly over the coming weeks.

Scott also shepherded Update.1 rc2, 691 (See http://download.laptop.org/xo-1/os/candidate/691/jffs2/). Preliminary release notes are at Test Group Release Notes#Build 691 Q2D13 .28RC2.29.

10. Sugar: Reinier Heeres finished up his coop for OLPC. Not only did Reinier finish up the the calculator activity in the OLPC system he created, he also fixed many other bugs in Sugar as part of the UI team during his coop period.

Simon Schampijer debugged a visual-control problem with Xulrunner (Ticket #6133) with Marco Pesenti Gritti. (It is probably an X driver bug.) He provided a first fix for a problem with the browser crashing when visiting certain web sites (Ticket #6108). The rest of the week was spent in testing.

Marco started on the code refactoring planned for Update.2. In particular the toolkit modules was split out into a separate package to ease maintenance and make licensing more clear. Also it's not necessary anymore to set SUGAR_PATH and SUGAR_PREFIX to run sugar or scripts such as the control panel. Marco built packages of Sugar and dependencies for Fedora 8 (this work is still in progress). The goal is to have something easier than jhbuild for people to develop activities or try out Sugar on a non-OLPC distribution. With Jani Monoses working on the Ubuntu packages, we should be able to cover a large part of the user community.

Marco also worked with the Pentragram and Eben Eliason on a Sugar demo for an upcoming MoMA exhibition, which will be open to the public.

Tomeu Vizoso is work on a possible solution to the slow startup time for activities. It is still too soon to know if or when his patches will land in our builds, but looks promising. Potentially, we could eliminate all initializing work not specific to activities.

Tomeu added some notes about he Sugar architecture to the wiki (See Sugar Architecture). The page is still incomplete; if you are interested in working on it, Tomeu will gladly answer any questions. He also added pointers to tickets to the pages in the wiki about the datastore redesign (See).

And, working with Jani, he fixed some license issues in the Sugar packages that will allow our packages to get into the Ubuntu 8.04 release in April. If things go as expected, Ubuntu users will be able to choose at boot Sugar as a desktop. Hopefully this will attract more users and developers to Sugar.

Sayamindu Dasgupta spent time helping Simon and Marco track down the cause of Browse activity slowing down after an upgrade from the Ship.2 release to the Update.1 RC release (Ticket #6046). It turns out that this is being caused by a combination of different issues—we believe that we have tracked them all down. Sayamindu has a new fontconfig package that takes care of issue #6048 along with a new version of Rainbow. The package is in Joyride and will be in the Update.1 release.

Erik Blankinship and Faisal Anwar at Media Mods created a screencasting activity this week to make it easy to create videos of what is happening on your screen, complete with audio narration. Also, Media Mods' newest version of the Record activity, which offers improved stability, made it into the Update.1 Release Candidate this week. Coming next to the Record activity is a control panel for adjusting image and audio settings, exif data, and some new recording modes: stop-motion and time-lapse.

Arjun Sarwal continues to work on the Measure activity; he is exploring graphing/plotting packages that can display logged data within Measure in a variety of different representations. After discussions it emerges that such graphing functionality would be useful in conjunction with a spreadsheet-like interface that can read data logged by the Distance activity (Acoustic Tape Measure) as well. Arjun is working on making Measure read and write data in CSV format so that the SocialCalc activity might be able to load and display the logged values.

Arjun discussed with Richard Boulanger the sensor opcode in Csound; more development on that front is expected to happen in the coming weeks. Finally, he spent time talking with Alexis Soffler regarding how she may be able to incorporate low-cost sensor peripherals into a chemistry curriculum that she is developing for the XO laptop, the first one being a low-cost temperature sensor probe.

11. Presence server: Morgan Collett has been working on documentation for presence and collaboration. See for the pages of Telepathy and Presence Service. Morgan also started a roadmap for presence that currently just documents open Trac items, but as we discuss priorities and features he’ll add more description: Talk:Presence_Service#Roadmap (feel free to comment there on anything not suited for a Trac comment).

Guillaume Desmottes changed the presence-server Jabber-account-registering policy (#6295) and resurrected the video-chat activity, which is now launchable again. He is waiting on new Farsight/Stream-engine packages to start testing; he also fixed some hyperactivity issues and track Salut crashers.

12. Translation: Sayamindu Dasgupta reports have new teams for Italian, Marathi, Sinhala, Vietnamese and Gujarati. He has an automated testing script for testing all the translated PO files for errors in the Pootle server. It currently tests only Spanish and Mongolian but Sayamindu plans on covering all languages by the next week. This should prevent build regression bugs due to malformatted or wrong PO files. He has added notes in the wiki on how to utilize the translation testing features in our web based translation management system, Pootle (Localization/Testing#Testing the PO files). Sayamindu also discovered a few cases where Pootle can become very slow, and discussed these with the upstream developers. They have suggested a few solutions, and he's trying to implement them in our deployment. The shifting of Pootle to the new server had caused some issues to crop up with the GIT integration—he managed to track them down and fix them. Sayamindu is at Gnunify, one of the grassroots level FOSS conferences in India, speaking about the OLPC.

Arjun built the xkeyboard-config package locally, in order to catch all of the recent changes to the xkb symbol files. Dennis Gilmore has built it on Koji; Arjun has tested it in Joyride and it is now approved to go into Update1.

13. Kernel: Andres Salmon pushed more (kernel) code upstream, uploaded mock to Debian (“and hey, it actually works; nice to be able to create Fedora chroots”), and updated yum packages for Debian.

14. Security: Michael Stone helped Tomeu debug his “prefork Rainbow-hack: and provided a tentative Rainbow rpm for Scott's “faster” branch. (These are all efforts towards tuning performance.) Michael merged Marcus Leech's “olpc-audit” filesystem permissions checker into olpc-utils; he prototyped patches to Sugar for improving sugar-install-bundle and for making the Journal automatically recognize developer keys and designated bundles on USB keys. Michael “stubbed out” wiki pages for several OLPC-maintained software artifacts and filed packaging tickets on behalf of John and Scott so that he and Dennis can track progress on the relevant packaging work.

15. Network: Michail Bletsas met with Latif Ladid, Chairman of the IPv6 Forum. The principle request on our part is for the forum to help us with setting up the necessary school-to-school IPv6 paths that will enable collaboration between children in different schools, countries, continents. Latif followed up with introductions to the two largest commercial IPv6 network operators.

Michail had a conference call with SES-Americom. They agreed to provide the (C-Band) space segment and internet termination (via their Maryland teleport) for our upcoming deployment in Haiti.

16. In the community: Peter Harrison and Michael Burns worked throughout the last two weeks to prepare the merging of the olpchelp.org and olpc.osuosl.org forums, which can be found at http://forum.laptop.org/. The migration happened Friday night without a hitch and we have more than doubled (800 users, 4,000 comments) the community discussing and supporting the XO laptop for Give 1, Get 1 donors. The support gang hopes to extend the site to all XO laptop users throughout the world with regional, language-specific forums over time.

Arjun Sarwal worked with advisors Josh Hehner and Jim Hopper to prepare a draft of the role of advisors document and channels of advising. The draft is posted on the Health page (See Health); feedback is invited from all. The agenda and other details of a conference call scheduled for 1PM (EST) on Sunday, 10 February, are also posted. Many thanks to all advisors for their support in this initiative.

Yoshiaki Sonoda, an enthusiastic grass-root volunteer and supporter of OLPC in Japan, is going to make two presentations about OLPC in Japan this month. The objectives are purely to draw people's attention to OLPC and to foster better understanding of OLPC philosophy in Japan. In addition, he hopes more people in Japan will take an interest in OLPC and subsequently contribute their ideas and resources to OLPC projects.

“OLPC roles in Human Security—from the aspect of Network Centric Strategy” Feb. 8, 2008, at Sunshine Convention Hall, Ikebukuro, Tokyo.

“Learning learning on Macintosh: Squeak Etoys and OLPC” at the Nagasaki Macintosh User Group Monthly Meeting (supported by Apple, Japan) Feb. 23, 2008, at Nagasaki International University, Nagasaki

These activities are supported continually by Mr. Abe, Squeakland.jp and other OLPC Japanese volunteer members.

More News

Laptop News is archived here.

You can subscribe to the OLPC community-news mailing list by visiting the laptop.org mailman site.

Press requests: please send email to press@racepointgroup.com

Milestones

Latest milestones:

Nov. 2007 Mass Production has started.
July. 2007 One Laptop per Child Announces Final Beta Version of its Revolutionary XO Laptop.
Apr. 2007 First pre-B3 machines built.
Mar. 2007 First mesh network deployment.
Feb. 2007 B2-test machines become available and are shipped to developers and the launch countries.
Jan. 2007 Rwanda announced its participation in the project.

All milestones can be found here.


Press

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More articles can be found here.

Video

Miscellaneous videos of the laptop can be found here.

Testimonials about my XO laptop

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