OLPC:News

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Laptop News 2007-07-28

1. FCC certification: Quanta's Kenny Chung reported that XO has been granted full FCC certification. This includes SAR (specific absorb rate) at less than 20cm (the distance between the WiFI antennas and a child can be less than 20cm). Other tests passed: Conducted Emissions; Radiated Emissions; Power Harmonics; Electro-static Discharge; Fast Transients and Burst Immunity; Surge Immunity; Induced Radio-Frequency Immunity; Power Frequency Magnetic Field Immunity; and Voltage Dips. Further UL and CE certifications are in process; these will require C-build machines for final approvals.

2. Free Drop: Mary Lou Jepsen and Quanta reviewed all the 10-point free-drop data that we have been collecting over since December 2006. The units are dropped on all corners, all side bumpers, and front and back. Initially, we had dropped onto plywood, but this spring we made the test tougher: we have been dropping on a hard steel plate, with and without a carpet. B4 units pass a 150cm 10-point drops onto a carpet-covered steel plate; a 105cm simulated slanted-desk "slide" onto a steel plate; and a 80cm 10-point free drop onto a steel plate. The laptop, when dropped on the antennas, withstands a 150cm drop. To put these data into perspective: a standard laptop only passes a 45cm 10-point drop on plywood (a much softer material than steel).

3. Trial-2 testing: Sometimes we easily miss the forest for all the trees, including the hundreds of bugs we deal with. This week we have a working mesh that does not require access points and operates across the full internet as well, the ability to share most of our basic activities including Chat, Write, Etoys, and Record. Kim Quirk and Jim Gettys conducted a “train” test (they commute by train without Internet access), which saw successful peer-to-peer picture sharing in the Record Activity and text, audio, and project sharing in the Etoys Activity. Sharing through the mesh is fun; it got the attention of a number of people on the train.

The functionality of Trial-2 code is at a very good state; it is now time to close it down and release it. To do that we are asking that no one checks in bug fixes or any code without an express OK from Jim, Kim or Dan Williams. At this point, we are only going to allow fixes associated with critical suspend/resume issues and critical regressions.

4. Trial-3 planning: Thanks to Simon McVittie and Dafydd Harries for coming to the OLPC office in Cambridge to work through some specific mesh, tubes, Salut, and Gabble issues and to help plan the Trial-3 feature set. Next week a team from OLPC and RedHat will be working with Pentagram to finalize the mesh, UI, and Journal features for Trial-3.

5. Etoys: The current focus of the Etoys team is stabilizing the Sugar integration. Bert Freudenberg led the effort and now an Etoy project can be saved into Journal. In the meantime, the other members of the team continue to improve the system. Takashi Yamamiya and Korakurider are working on the interface with gettext; now, the phrases used in the Etoys system can be translated by standard external tools. Yoshiki Ohshima and Bert made the system locale conscious; the system switches language upon starting. Scott Wallace has made improvements to some UI elements, including simplifying the sound recorder. Scott also helped Kim Rose, Alan Kay, and Rebecca Cannara with the documentation effort. Ted Kaehler worked on improving some example Etoys that will be bundled with the distribution.

6. Temperature testing: Joel Stanley and Arjun Sarwal set up a food warming oven in the OLPC office. The oven is large enough to house eight fully opened XOs and allows us to examine the behavior of the laptops under temperatures ranging from a warm 40°C, up to a toasty 60°C and above. Some preliminary tests were conducted, examining the operation of the battery charging systems under the extreme heat that may be encountered by, say, a laptop sitting in full sunlight. One motivation for this testing is that the NiMH batteries that are used in some of the XOs lose the ability to be charged above 55°C. (The newer LiFePO4 technology allows charging above these temperatures, for when the need arises.) We are pleased to report the XOs ran flawlessly in the extreme heat, even when the oven’s unpredictable thermostat inadvertently allowed the temperature to reach 68°C. Further testing will take place over the coming weeks.

7. Touchpad: Joel also tested the new touchpad/keyboard subsystem from ALPS, verifying the new power-saving mode it allows. We can successfully power it down, saving almost 12mW, and bring it back out of power saving mode when the user requires it again.

8. Backup: Chris Ball worked with Scott Ananian on the USB backup/restore script for Trial-2. By putting restore into the activation ramdisk, we have backup/restore happening with one command (./usbupgrade) in the developer console. We would like to get that down to zero commands, though, by having the autoreinstallation image make the backup automatically too.

9. Performance: Marco Gritti, Tomeu Vizoso, Dan Williams, and Chris Ball explored reducing our memory usage to make the current images usable on B2-1 laptops (with only 128M of DRAM). All in all, there should be 20M of (resident) memory that we can reclaim so far for Trial-2; 10M due to Sugar importing libraries and icons that it doesn't need, and 12M for the heavyweight DHCP server that we run when associated with an access point. We'll keep working on this, as it has a positive impact on performance on all versions of the XO.

10. School server: Scott Ananian, Dan Margo, and John Watlington pushed forward on School server software builds. A stumbling block is automating the install from a live CD. Dan ended his summer internship this week. His efforts in this area have been appreciated, and we hope that he continues to help remotely in the future.

11. Embedded controller: Richard Smith discovered that the SCI wakeups were not handled properly and the power button was being asserted on resume (unnecessarily), causing spurious power button events. Richard also discovered a race condition that was the reason for some EC timeouts; Andres Salomon added a 2ms delay in the kernel as a workaround, while Richard is working on a proper fix for the EC. After three weeks of chasing a bug, the cause of a NiMH battery-charging problem has been found. Q2C19 will fix this bug. The source of the mistaken “power button” on resume was located and fixed. With these EC bugs fixed, suspend/resume code should begin to function as expected.

12. Donations to the OLPC Foundation can now be made by credit card through Google Checkout or with a PayPal account. The link to the giving site is http://laptopfoundation.org/en/participate/. OLPCF continues to accept checks as well.

Upcoming Highlights:

Jul 31 – Aug 6 Wikimania, Taipei
Aug 1–3 Squeakfest07, Chicago, IL

More News

Laptop News is archived at Laptop News. Also on community-news.

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

  1. redirect OLPC:News#Press

More articles can be found here.

Video

Miscellaneous videos of the laptop can be found here.

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