Re: anyone want XOrduino or XO Stick bare boards

[C. Scott Ananian]

I have a bunch of these as well, and even a few sets of components. Like
Paul, I put together another one every so often when I need a
microcontroller for a project, but I'm happy to share my stash with other
good homes.
  --scott

On Mar 10, 2017 7:13 PM, "Paul Fox"  wrote:

> paul wrote:
>  > doing some cleanup today, i found that i have 10 XO Stick and 14
>  > XOrduino bare boards that i'm happy to mail to anyone that can make
>  > use of them -- either all at once, or as few as one to a "customer".
>
> i should have been more clear, since someone has already asked -- i'm
> not charging anything for the boards.  these circuit boards are all
> surplus that was saved from the goodwill industries and the dumpster
> while we were closing down the OLPC offices in somerville several
> years ago.
>
> i'll accumulate requests (if any) for a week or so, then send them out.
>
> paul
>
>  >
>  > i've used a couple of the XO Stick boards for my own projects, and i'm
>  > setting aside a couple more for future use.  i also built up an
>  > XOrduino, to prove it could be done (it wasn't easy -- hand-soldering
>  > SMT parts is harder than it looks), but i'm not sure i ever even
>  > booted it.  i'm happy to give that board to someone too.
>  >
>  > i'm not on any of the deployment lists, or the unleashkids -- feel
>  > free to forward this message if you think someone not on devel would
>  > be interested.
>  >
>  > for a reminder of what i'm talking about see:
>  > http://cananian.livejournal.com/66129.html
>  > http://cananian.livejournal.com/66654.html
>  > http://cananian.livejournal.com/66895.html
>  >
>  > i have notes i made while assembling the XOrduino which i can share.
>  > not sure i have anything similar for the XO Stick -- i recall it was
>  > a piece of cake by comparison.
>  >
>  > paul
>  > =-
>  >  paul fox, p...@laptop.org
>  >
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> =-
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Duolingo and literacy

[C. Scott Ananian]

I'm in a presentation by Luis von Ahn, founder of DuoLingo, and I asked him
if he had any plans to expand to literacy.

He replied that they will be releasing a reading and typing (not writing,
which he thought had poor ROI) app next year.

This makes me extremely excited.
  --scott

PS. I should have followed up re: teaching English literacy directly rather
than teaching a native language first.
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Re: Duolingo and literacy

[C. Scott Ananian]

SJ and I did get a chance to follow up with him afterward and suggest that
they might considering teaching English literacy directly to non-native
speakers (as we did in our Ethiopia pilot, rather than only teaching
students in their native language; of course DuoLingo doesn't support a
large number of languages, so allowing folks to skip directly to English
would greatly increase their reach).  They are big on A/B tests and
quantification over there, I think we convinced him it was an interesting
hypothesis to test.

SJ asked how one could help with the literacy effort and he gave us some
contract information.  If any of the OLPC crew is interested, drop me (or
SJ) a line and we'll try to hook you up.

I think they might actually be able to make a significant dent in the
literacy problem.
  scott
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Re: Fwd: XO Problems (4 Problems)

[C. Scott Ananian]

A related question.  I'll try to phrase this delicately -- what's the
relationship between Walter's Sugar 100 build and the latest OLPC
kernel?  Can I safely assume that SugarLabs is the current keeper of
the flame and has all the latest hardware-support bits (I hope so!).
Gonzalo pointed me to a different build.  Can someone explain the
different sources of bits and development to me?
  --scott
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Re: Fwd: XO Problems (4 Problems)

[C. Scott Ananian]

Thanks!  I forwarded everyone's responses on to Douglas, with pithy
descriptions of who you all are and the exciting things you do and
countries you live in, to give him a taste of the broader OLPC
community.  I'll probably install the latest image on his machine in
the next few weeks, and I'll let you know if we find any issues (or
maybe I'll teach him to report them himself!).

Walter, let me know if you ever do any Boston-area SugarLabs
activities, he's reached the age where he'd be an enthusiastic
participant.  (Although not a Python coder yet, he's mastering Scratch
first.)
 --scott

On Mon, Nov 25, 2013 at 4:53 PM, James Cameron qu...@laptop.org wrote:
 G'day Scott,

 There have been no significant changes to the hardware support since
 the 13.2.0 release, although Daniel Drake has contributed some fixes
 I've seen in the various git repositories.

 Firmware fixes yet to be included in a release are:

 - a fix for erroneous low-battery power downs that may occur between
   the time the runin tests are used and when power cable and battery
   are removed for shipping, (released as XO-4 EC 0.4.11),

 - a minor fix for ntp-set-clock, relevant only for deployments who
   plan to use NTP in their firmware boot script or USB drives, (not
   released, but is in repository),

 - a fix for four game key reflash over HTTP, relevant only for
   deployments who plan to use a reinstall image available over
   wireless; e.g. short range 802.11n dongles attached to a server,
   (not released, but is in repository),

 I've been working on a fix for the #12694 hang of the XO-4 mwifiex
 wireless driver that may occur when a laptop experiences heavy demand
 for memory at the same time as a large download.  I'm not ready for
 wider testing yet.

 Gonzalo and Walter are working on a deployment image, in a different
 version number namespace, for which they have used the number 13.3.0,
 in which most of the change is in Sugar and activities.  It is based
 on 13.2.0 hardware support.

 One of the Sugar changes might be considered hardware support;
 compatibility with WPA Enterprise and hidden SSID access points.
 There might be others, I haven't checked.

 There are no hardware changes that I'm aware of in the manufacturing
 pipeline, so no new hardware support needed yet.

 On Mon, Nov 25, 2013 at 11:59:59AM -0500, C. Scott Ananian wrote:
 A related question.  I'll try to phrase this delicately -- what's the
 relationship between Walter's Sugar 100 build and the latest OLPC
 kernel?  Can I safely assume that SugarLabs is the current keeper of
 the flame and has all the latest hardware-support bits (I hope so!).
 Gonzalo pointed me to a different build.  Can someone explain the
 different sources of bits and development to me?
   --scott

 --
 James Cameron
 http://quozl.linux.org.au/



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Fwd: XO Problems (4 Problems)

[C. Scott Ananian]

Anyone have any suggestions for my six year old friend? IIRC startup volume
is persistent, but I can't remember how it is adjusted. The rest might be
helped by upgrading to the latest XO4 build?
  --scott
-- Forwarded message --
From: Douglas Rogers purpleairpl...@gmail.com
Date: Nov 24, 2013 12:00 PM
Subject: XO Problems (4 Problems)
To: csc...@cscott.net
Cc:

hi scott it's Douglas. Can you help me make my xo work?
1) When I turn on the computer,the ''on music'' is too loud.(so loud I have
to cover the speakers)
2) In scratch when I switch projects all the sprites from the old project
stay there.
3) My XO freezes up a lot
4)  If I use the touch screen I can't start using the mouse again
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Sugar Collaboration with a Tow Truck

[C. Scott Ananian]

I mentioned this project a while ago on IRC, and cjb has spread it around,
but manuq reminded me that I never actually posted it to a mailing list.

The mozilla Tow Truck project:
  https://towtruck.mozillalabs.com/
is a very nice framework for real-time collaboration in the context of web
apps.  It has a plugin architecture, so you can add your own editor
components for (say) building a turtleart program together.  It also does a
lot of the hard plumbing, like friend-discovery, and necessities, like
real-time chat on top of the collaboration.

This would be a great foundation for web app Sugar collaboration.  With
the native plugin approach I've previously advocated, you could build
native Sugar plugins so that TowTruck collaboration could interoperate with
native Sugar collaboration as well (ie, share friends lists, say).

It's a project worth exploring, and potentially a set of wheels worth not
reinventing.
  --scott

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Popular Science article on OLPC project.

[C. Scott Ananian]

The following mostly-critical article was mentioned on IRC:

http://www.popsci.com/gadgets/article/2013-07/one-laptop-childs-de-evolution

It's worth keeping the criticisms in mind while working to invalidate them.
 --scott


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Issues from my 6-yr-old beta tester.

[C. Scott Ananian]

The build I installed on my beta-tester's XO4 is about a month old.
I'm hoping the following are known issues, and all I have to do is
update the build.  (Can I use olpc-update to do that?)

* The sound in Scratch and Memorize is scrambled; sound appears to be
piped from /dev/random and hurts my ears.
* Tam Tam Edit had different sound issues -- the playback cursor
wandered all over the screen when play was pressed, sometimes moving
backwards.  The sound wasn't scrambled, but I'm not convinced that the
sequencing was correct (I forget exactly what the demo is supposed to
sound like, but it didn't sound right to me.)
* When you capture a new costume in Scratch using the camera,
everything appears to have a strong yellow cast.

He's also missing the top-right keycap from his crunchy keyboard. He
was very vague about how exactly that happened...
  --scott

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Re: Shipping bigger fonts by default for greater glyph coverage

[C. Scott Ananian]

IIRC its only the CJK fonts which really bloat the build.  There's an old
bug in trac which discussed fonts at length; it might be worth digging that
up to ensure we're still covering all the languages we were covering then.
  --scott
On Sep 5, 2012 6:58 PM, Chris Leonard cjlhomeaddr...@gmail.com wrote:

 On Wed, Sep 5, 2012 at 6:58 PM, Mikus Grinbergs mi...@bga.com wrote:
  Something to watch out for is the content of /usr/lib/locale.
 
  Having been caught several time in the past with C as the only language
  recognized, I now pay attention to the content of that directory.  [For
  instance, allowing a Fedora upgrade of the package 'glibc-common' could
  add an extra 80 MB into that directory.
 
  mikus

 That is an interesting and important point.  I wonder if the langpack
 install could be adjusted to bring it's locale with it, if needed?

 cjl
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Re: Impossible to set date in 11.3.0?

[C. Scott Ananian]

It seems like all that is necessary is to add a test for a secured laptop
to allow this patch to go upstream, right?
(This approach looks very similar to what I did in OLPC build 603 or so.)
  --scott
On Aug 25, 2012 7:08 PM, Jerry Vonau jvo...@shaw.ca wrote:

 On Sat, 2012-08-25 at 18:25 -0400, Walter Bender wrote:
  File a ticket and someone may jump in to tackle it.
 
  -walter
 

 see http://dev.laptop.org/ticket/11004


  On Sat, Aug 25, 2012 at 3:24 PM, Martin Langhoff
  martin.langh...@gmail.com wrote:
   On Sat, Aug 25, 2012 at 2:26 PM, C. Scott Ananian csc...@laptop.org
 wrote:
   Surely we can distinguish secured from unsecured laptops and allow
   unsecured laptops to set the date?
  
   Sure. Nobody's done the UI work for that, Sugar-side.
  
- In all builds, hwclock is available from cli
- On 11.3.x  and earler builds you can install the appropriate gnome
   control panel.
- On 12.x.y builds, gnome control panels aren't so easy to make work,
   'cause they need clutter.
  
   Also, we should run ntp by default, or at least ntpdate on an NM hook.

 We do that in Australia builds, need nptdate to be added to the image,
 setup /etc/sysconfig/ntpdate and the NM hook.

 # toggle setting the rtc
 sed -i -e s/SYNC_HWCLOCK=no/SYNC_HWCLOCK=yes/ /etc/sysconfig/ntpdate

 # call ntpdate when connected
 cat  EOF  /etc/NetworkManager/dispatcher.d/10-ntpdate
 #!/bin/sh

 if [ \$2 = up ]; then
 if [ ! -e /tmp/ntpdate ]; then
 touch /tmp/ntpdate
 /sbin/service ntpdate restart || :
 fi
 fi
 EOF
 chmod 755 /etc/NetworkManager/dispatcher.d/10-ntpdate

 Jerry


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Re: Setting the time

[C. Scott Ananian]

On Mon, Aug 27, 2012 at 10:05 AM, Samuel Greenfeld greenf...@laptop.org wrote:
 In any case if OLPC or Sugarlabs wants to formally integrate NTP services
 into our products, we should be polite and ask ntp.pool.org if we need our
 own vendor subdomain.  These allow the NTP pool to shut off misbehaving
 clients without affecting other users, and Fedora and CentOS already have
 their own.

We already did this (the first time I fixed this bug, years ago).  I
believe we have olpc.ntp.pool.org, although I'll have to dig up the
email from my archive to double-check.  We also got permission to use
fedora's pool at the same time, because it was more suitable for the
upstreamed version of the patch.
  --scott

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Impossible to set date in 11.3.0?

[C. Scott Ananian]

A friend has 11.3.0 installed on his son's XO 1.5.  The kid complained
that the date was wrong on his XO, and he couldn't figure out how to
set it.  Indeed, the Time and Date control panel only has time zone
selection, and no sort of network time program seems to be included in
the build.  Was this an intentional omission?  How is the date
supposed to be set in 11.3?
  --scott

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Re: Impossible to set date in 11.3.0?

[C. Scott Ananian]

Surely we can distinguish secured from unsecured laptops and allow
unsecured laptops to set the date?

I know I implemented this once...
  --scott

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Re: XO-1.75 OpenFirmware serial terminal

[C. Scott Ananian]

On Wed, Mar 28, 2012 at 10:44 PM, John Watlington w...@laptop.org wrote:
 I'd love to see serial terminal preloaded, but also acknowledge that I'm the
 one pushing against a 2MB SPI Flash ROM.   How about specifying
 a location in the main build, where another 20KB of example OFW code
 isn't as important ?   Say:

 devalias lib int:2  # build a pointer to the library into OFW

 dir lib:\ofwlib\  # See what is available (anyway to avoid the 
 dir name ?)
 fload lib:\ofwlib\serial.fth
 serial

 We could also move some of the existing non-essential OFW utilities there as
 SPI Flash ROM space gets tighter, such as emacs.

Incidentally, we could also add VFAT long filename support to such an
auxilliary location, so that it's not part of distributed OFW and
keeps Mitch far from culpability.
  --scott

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XO Sticks and XOrduino

[C. Scott Ananian]

I have about 20 XO Sticks and XOrduinos to give away to developers.  Details at:
  http://cananian.livejournal.com/66654.html
 --scott

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Re: Engadget post on XO Touch

[C. Scott Ananian]

Presumably with the standard multi-touch X support, which is landing
in Linux all over.  That's how the XO-3 worked, at least, although
that was traditional capacitive touch; I don't think there's an actual
Neonode driver in existence anywhere yet.
  --scott

On Tue, Jul 31, 2012 at 8:54 PM, Bert Freudenberg b...@freudenbergs.de wrote:

 On 26.07.2012, at 20:21, Mike Lee wrote:

 Here's a cool demo of the Neonode multitouch frame:

 http://www.slashgear.com/neonode-3d-touch-headed-to-tablets-and-phones-hands-on-28215933/

 Not only multi-touch, but also entry direction and tilt. For a dollar!

 Well, for tilt you would need to stack multiple frames on top of each other 
 as they did in that prototype. For a touch-screen you would want it to be as 
 thin as possible, that would mean single-layer. The Kindle Touch and Nook use 
 Neonode zForce touch sensors, too. Here's a nice animation showing the 
 principle:

 http://www.neonode.com/solutions/zforce

 Does anyone know how the multi-touch stuff is going to be exposed in Linux?

 - Bert -



 Seems like this would be great as a retrofit kit.

 Mike

 On Thu, Jul 26, 2012 at 11:09 PM, Sameer Verma sve...@sfsu.edu wrote:
 www.engadget.com/2012/07/26/olpc-xo-touch-1-75-to-use-neonode-tech/

 The post says as yet unreleased XO 1.75. What's the official status
 on the 1.75? Still as yet unreleased?

 cheers,
 Sameer


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Re: Developer XO laptop loan or buy - Speakeasy project

[C. Scott Ananian]

On Wed, Jun 13, 2012 at 6:17 PM, Martin Langhoff
martin.langh...@gmail.comwrote:

 On Wed, Jun 13, 2012 at 11:37 AM, Lester Leong lester.ble...@gmail.com
 wrote:
  Scott - could you point me in the right direction as far as a good
  JS/HTML5 framework?

 Keep in mind that _today_ XOs don't ship with a workable JS runtime
 environment other than the webbrowser.


...which is a perfectly fine runtime environment.  And writing a python
wrapper that functions like PhoneGap is perfectly straightforward; the
wikipedia and other apps on the XO already do it.

As for JS/HTML5 frameworks, there are a bazillion of them.  Some popular
bits:
 http://twitter.github.com/bootstrap/
 http://enyojs.com/
 http://knockoutjs.com/
 http://brian.io/lawnchair/
 http://sproutcore.com/  (although this is geared for client/server)
Lots more random stuff linked from:
 http://wiki.laptop.org/go/Nell/InterestingJavascriptLibraries
 http://dailyjs.com

 --scott

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Re: Developer XO laptop loan or buy - Speakeasy project

[C. Scott Ananian]

On Tue, Jun 12, 2012 at 9:15 PM, Lester Leong lester.ble...@gmail.comwrote:

 As for Javascript, how? Javascript can't handle backends without some
 significant running around - everything's gotta be database driven.


I think you need to look again at modern Javascript/HTML5 toolkits.
There are databases.  There are routers.  You don't need anything else.
 --scott
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Re: Developer XO laptop loan or buy - Speakeasy project

[C. Scott Ananian]

On Tue, Jun 12, 2012 at 4:16 AM, Chris Ball c...@laptop.org wrote:

 Hi Lester,

 On Mon, Jun 11 2012, Lester Leong wrote:
  I think it could just be as easy as having a collection of multimedia
  and gamifying it. I thought of having a set of flashcards with audio -
  then many things could be done with that. Audio to picture matching.
  Finish the sentence. Multiplayer races. Pictures in a series to denote
  context, etc. It could just be that simple. Would be really trivial to
  implement as well. I even thought of implementing it as web served
  pages so that the whole thing could exist in website form - in remote
  locations without Internet, maybe the pages can be locally
  stored/hosted.

 I like this idea, and I'm happy to see that you aren't trying to do too
 much.  I think develping this as a set of webapps sounds like a fine
 start -- it allows you to work on it more easily with other developers,
 who don't share your platform, too.

  Anyway, the reason I would like an XO is because I'd like to get a
  feel for user interface, as well as the limitations of it, from the
  very beginning. It would help guide design immensely.

 Did you know that it's easy to run OLPC's user interface, Sugar, on
 non-OLPC laptops?  Here's a recent guide written by Simon Schampijer:

 http://wiki.sugarlabs.org/go/Activity_Team/Activity_Development_Fedora17

 There isn't much (if anything) of the user interface that's dependent on
 the hardware; you can see it all by running Sugar locally too.



Also, for what it's worth: our current literacy deployments in Ethiopia are
using the Motorola Xoom Android tablets.  I've found that writing apps
using HTML5 toolkits is a great way to make them portable across XOs and
Android tablets and educators sitting at their desktops who are in a
position to offer advice.

As two examples, you might look at:
  http://cscott.github.com/nell-balloons/
which is the core of a simple matching game for assessment.  At some point
you have to be able to determine if the kids are actually learning
anything, and their speed/accuracy in matching words with sounds/pictures
is a reasonable way to measure this, with good support in the educational
literature.

At a different point in the continuum:
  http://cscott.github.com/nell-colors/
is a simple drawing program that helps kids learn handwriting by
recognizing when they draw letters (lowercase only for now, this is a
work-in-progress).

My experience is that it takes a long time to actually polish an app to the
point where kids will enjoy using it *and* you've tuned all the
'gamification' aspects such that the kid is motivated to do what you want
to do (instead of, say, deliberately choosing wrong answers because the
fart sound it makes it more fun).
  --scott

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Re: Developer XO laptop loan or buy - Speakeasy project

[C. Scott Ananian]

..and if you can replace the php with javascript, your life will be
even easier. ;)
 --scott

On 6/12/12, Gonzalo Odiard gonz...@laptop.org wrote:


 Another thing is, with regards to webapp implementation - I have
 thought of using PHP/HTML5/Javascript.



 If you can replace PHP by python, your live will be a lot easier including
 your work as a activity in sugar.

 Gonzalo



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Short paper on Nell (XO-3)

[C. Scott Ananian]

Chris Ball, Michael Stone, and I submitted a short paper about Nell's
design for the 2012 Interaction Design and Children conference.  It
contains a much more coherent description of our ideas and goals than
the random fragments at http://wiki.laptop.org/go/Nell.

The paper is posted at http://cscott.net/Publications/OLPC/idc2012.pdf

Comments and feedback welcome!  Assuming the paper is accepted, we
will still have to revise for publication, so also let us know if you
found any of our arguments confusing, wrong, or simply disagree, so we
can do a better job for the final paper.
  --scott

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Re: [Sugar-devel] automatic backlight control

[C. Scott Ananian]

Just to reinforce a few points which maybe might not be clear to
people who haven't played with the new hardware:

1) the switch point is set that *you cannot tell when we turn the
backlight off*.  Ie, the threshold is so high that by the time we turn
it off, you couldn't never have told whether the backlight was on or
not.  This is very different from the auto dim feature in Macs, for
example.  (And it's the primary reason why the switch to monochrome
was so visible -- you couldn't tell that we were turning the backlight
on and off, you could only tell that the images on the display were
shifting greyscale values intermittently for no obvious reason.)

2) this is a very important power-saving feature for young kids, who
generally aren't savvy enough to manually do all these measures which
prolong battery life.  So, even if power tweakers might want a
little more control, it's important to make the default behavior as
power-friendly as possible (especially as we move further into
deployments where access to power is a big big deal).  We should keep
in mind the trade-offs here.

  --scott

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Re: 11.3.1 build 10 released for XO-1.75

[C. Scott Ananian]

On Wed, Nov 9, 2011 at 3:43 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
 The suspense resume build, featuring suspend resume that may or may
 not resume.

IIRC, some of the resume crashes are in fact suspend crashes.  So it
may not even suspend.  More suspense!
 --scott

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Re: XO-1.75 relative performance

[C. Scott Ananian]

And note that Jon's original advice was based on the absence of *EGL*
support in clutter at the present time.  The fact that you can run/not
run gnome-shell on desktops with full *GL* support is not relevant.

This thread has diverged.  GTK3 is not gnome3 is not gnome-shell; EGL
is not GL; Sugar is not Gnome.
 --scott

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Re: XO-1.75 relative performance

[C. Scott Ananian]

On Wed, Nov 2, 2011 at 12:49 AM,  fors...@ozonline.com.au wrote:
 For what its worth, the XO-1.75 is currently about half the speed of the XO1.5

 Measured with Turtle Art

 repeat 5000
  fwd 100
  back 100
 print time

 but as said, its early days for the 1.75 with optimization to come

Yeah, this is almost certainly due to the terrible graphics driver
performance which jon nettleton is working to fix.

A pure-CPU benchmark (maybe something in Pippy?) would be a little
more reliable.  But anything involving floating point will suck,
because we're not using the hardware floating point support yet.  So
much software to tune...
 --scott

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Narrative Interfaces at OLPC

[C. Scott Ananian]

I just posted an announcement for some invited talks we're having at
OLPC's new offices this Friday:
  http://cananian.livejournal.com/64747.html
It will all be live-streamed at:
  http://www.ustream.tv/channel/cscottnet
 --scott

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Re: [IAEP] Turtles All The Way Out

[C. Scott Ananian]

On Mon, Jun 6, 2011 at 8:11 PM, John Gilmore g...@toad.com wrote:
 Don Hopkins worked on a PostScript-based window system (HyperLook)
 that would let you flip over an object on the screen to see behind
 it a control panel with the guts of its implementation visible.  You
 could modify those, then flip it back and it would resume running.
 See: http://www.art.net/~hopkins/Don/hyperlook/index.html and
 http://www.art.net/~hopkins/Don/simcity/hyperlook-demo.html .

Self: The Movie is also worth watching.  The self guys thought that
continuous execution of the code was important for liveness, along
with some other views (like direct correspondence between objects and
representation) which I don't think I actually agree with.  But still,
worth thinking about:
   http://www.smalltalk.org.br/movies/
  --scott

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Re: [IAEP] Turtles All The Way Down

[C. Scott Ananian]

On Fri, May 20, 2011 at 11:09 AM, Alan Kay alan.n...@yahoo.com wrote:
 Smalltalk actually got started by thinking about a way to make a child's
 Logo-like language with objects and pattern matching that could express its
 own operating system and environment.

 It is very tricky to retain/maintain readability (so the first Smalltalk was
 also an extensible language not just semantically but syntactically).

 With a tile language, this is really worth thinking about, since using tiles
 suggests ways to extend both the form and the meaning of the tiles.

I've written a follow-up post, musing on the readability aspect Alan
mentioned above:
  http://cananian.livejournal.com/64330.html

Is it worth trading a very simple and direct syntax like:
  var Point = {};
  Point.x = 0;
  Point.y = 0;
  var Point3D = Object.create(Point);
  Point3D.z = 0;

for the more readable:

Class(Point, {
has: {
x: {is: ro},
y: {is: rw},
},
})

Class(Point.ThreeD, {
isa: Point,
has: {
z: {}
},
})

at the cost of introducing additional complexity into the object
creation process.  The complexity is in a library, so the base
language is kept small -- but it's still more turtles thrown onto the
stack that you have to understand.

Returning to Alan's point about tiles -- the nice thing is that you
could define a custom tile for the Class() syntax above, with
pretty selectors to help you select parent class, slot attributes,
etc.  But perhaps it's better just to keep the conceptual model small
-- then you don't need fancy GUI widgets to help you out.

For a more concrete example, you might want to read through:
  
https://github.com/cscott/TurtleScript/blob/beeba5c138d88af40297f93689ecbe7721724819/crender.js#L333

starting at line 333 or so.  That's a widget library written in
Simplified JavaScript/TurtleScript which uses prototype inheritance
extensively.  You can do clever things like swipe the implementation
of a function from a totally different class; see how we do multiple
inheritance around line 661.  Is the Joose syntax an improvement?
  --scott

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Re: Raspberry Pi $25 computer

[C. Scott Ananian]

To sweeten the pot, I'm offering a delicious stone soup for anyone who those
who pitch in on the port.  You need only supply a few extra ingredients.
  --scott
On May 21, 2011 10:35 PM, moku...@earthtreasury.org wrote:
 FYI. Anybody who would like to port Sugar to a $25 computer (requiring
 only monitor, mouse, and keyboard) should contact Eben, and let us
 know too.

 -- Forwarded message --
 From: Edward Cherlin echer...@gmail.com
 Date: Sat, May 21, 2011 at 22:10
 Subject: Re: [Sur] linux system por $25
 To: Eben Upton eben.up...@gmail.com

 On Sat, May 21, 2011 at 12:22, Eben Upton eben.up...@gmail.com wrote:
 Hi Edward
 Thanks for your mail, and apologies for the delay in replying. The
 devices should be available to the general public later in the year;
 I'll add you to our mailing list, and will keep you posted as we get
 closer to launch.

 Thank you.

 We've heard of Sugar, but need to find out more about it. Do you think
 it's suitable for a machine with limited processing power and only
 256MB of RAM?

 That's what it was designed for.

 http://wiki.laptop.org/go/Hardware_specifications
 AMD Geode 433 Mhz processor
 256M RAM
 Fedora Linux

 http://wiki.sugarlabs.org/go/Getting_Started
 http://wiki.sugarlabs.org/go/Activities

 Cheers
 Eben Upton
 Director, Raspberry Pi Foundation

 Follow us @Raspberry_Pi on Twitter


 On Fri, May 6, 2011 at 5:07 PM, Edward Cherlin echer...@gmail.com
wrote:
 Your Web site asks

 Do you have open-source educational software we can use?

 The answer is Yes. Sugar education software runs on a variety of Linux
 distributions, including Ubuntu. It is currently in the hands of more
 than 2 million children.

 We plan to develop, manufacture and distribute an ultra-low-cost
 computer,
 for use in teaching computer programming to children.

 Sugar includes Python and Smalltalk (Etoys). One Laptop Per Child XO
 computers also run Open Firmware, written in FORTH, and including the
 complete FORTH development library, the editor, and an assembler. OFW
 is available for systems based on ARM processors.

 The Sugar Labs Replacing Textbooks project, which I started recently,
 will include a variety of materials for teaching programming and
 Computer Science, and for applying those languages to every school
 subject. We have compiled a list of successful projects for teaching
 programming in the elementary grades, including projects using Python,
 Smalltalk, Logo, LISP, BASIC, and APL.

 The real question is one that Seymour Papert asked in 1970: Can we
 design an environment in which children learn math and programming
 languages as readily as they learn human languages, largely from each
 other? Some of us think so, and we are working on it.

 I will be happy to answer further questions, or to direct you to those
 who know more about some aspects of Sugar than I.

 -- Forwarded message --
 From: Sean DALY sdaly...@gmail.com
 Date: Fri, May 6, 2011 at 11:28
 Subject: Re: [Sur] linux system por $25
 To: OLPC para usuarios, docentes, voluntarios y administradores
 olpc-...@lists.laptop.org
 Cc: Gleducar gledu...@gleducar.org.ar


 http://lists.sugarlabs.org/archive/marketing/2011-May/003273.html


 On Fri, May 6, 2011 at 5:23 PM, Daniel Ajoy da.a...@gmail.com wrote:
 linux system por $25

 http://www.raspberrypi.org/

 --
 Edward Mokurai

(#40664;#38647;/#2343;#2352;#2381;#2350;#2350;#2375;#2328;#2358;#2348;#2381;#2342;#2327;#2352;#2381;#2332;/#1583;#1726;#1585;#1605;#1605;#1740;#1711;#1726;#1588;#1576;#1583;#1711;#1585;
 #1580;) Cherlin
 Silent Thunder is my name, and Children are my nation.
 The Cosmos is my dwelling place, the Truth my destination.
 http://wiki.sugarlabs.org/go/Replacing_Textbooks

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Re: [IAEP] Turtles All The Way Down

[C. Scott Ananian]

I'm familiar with the processors designed for specific high-level
languages.  There was another generation of them built for Java
(microblaze, picoblaze, etc) and some of those are even still
commercially significant (they run Java subsets on smart cards).

I'm not terribly interested in those processors.

More in tune with the turles all the way down agenda is the work
done on compiling high level languages to hardware. It's not that the
hardware chipset runs turtlescript (that's not really giving you any
additional insight into the operation of the hardware), but that the
hardware is *described* in turtlescript.  I've made some modest
contributions to this in the distant past
(http://flex.cscott.net/SiliconC/paper.pdf).

That said, there is *zero* chance that this work will result in
hardware suitable for the kids we care about.  So let's stop talking
about it.

 I once used a tile-based UI in a commercial database program. It was
 horrible once we got past the toy examples. [...]
 Of course. I would say that perhaps 40 or 50 blocks is a reasonable limit.
 After that, you should be writing subroutines to go in Python blocks, and
 not very long after transition to pure Python.

Let's find out.

I've written almost 4,000 lines of code in my tile based language so
far.  So far I've been typing it.  I hope to leave the keyboard behind
soon.  And then we'll see whether I agree with you or not.
   --scott

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Turtles All The Way Down

[C. Scott Ananian]

I've done a little more work on Turtles All The Way Down, which I
(very briefly) discussed at EduJam.  I actually wrote a garbage
collector in TurtleScript for TurtleScript on Sunday.  Brief writeup
here:
   http://cananian.livejournal.com/64140.html
and exhaustive mind-numbing detail here:
   http://cscott.net/Projects/TurtleScript/

No actual turtles yet!  I'm going to have to fix that soon.
  --scott

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Re: Turtles All The Way Down

[C. Scott Ananian]

2011/5/20 NoiseEHC noise...@freemail.hu:
 1. Why do the bytecode stuff? JS seems to be a perfectly good code
 representation to me and it can be run much faster compared to a naive
 bytecode interpreter or compiler written without the resources of the
 Chrome/V8 team.

It's true.  As described in my blog post, the VM work was an
experiment to see how far down the turtles could go.  As the Klein
VM and other examples have shown -- pretty far down!  Even if you end
up running the language in the fast V8 VM, you might want to have a
version with somewhat lower performance which is 99.9% view
source-able.  But I really should be concentrating on the
higher-level stuff at the moment.

 2. Why do you want to serialize the stuff? Is not it enough to serialize
 just the JS code + screenshot and on load run it?

It relates to the desire to be able to do prototype-style development,
where you modify existing objects to create new functionality.  (Think
etoys.)  Once you've got a bunch of user-modified objects floating
around, you have to start thinking about how to save/load them.

 3. Why is the pervasive undo necessary? Only for debugging?

That relates to the goals of Sugar, leaking through into TurtleScript.
 It's actually pretty easy to screw up your VM pretty badly if you can
actually access it down all the way to the bottommost turtle.  Once
you've done this, it would be nice to be able to recover gracefully --
or at least, more gracefully than toss the saved image and restart.
Supporting cheap snapshots of the system image is one way to do this.

 BTW cool project, that is exactly what I wanted to do, now I do not have
 to... :)

Oh no!  That's the opposite of my intended goal in talking about this
stuff -- at some point I badly need other people to adopt the ideas
and carry on with the implementation, as I'm unfortunately still a
single-core human.
  --scott

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Re: [IAEP] Turtles All The Way Down

[C. Scott Ananian]

On Fri, May 20, 2011 at 11:09 AM, Alan Kay alan.n...@yahoo.com wrote:
 This is nice!

 Smalltalk actually got started by thinking about a way to make a child's
 Logo-like language with objects and pattern matching that could express its
 own operating system and environment.

 It is very tricky to retain/maintain readability (so the first Smalltalk was
 also an extensible language not just semantically but syntactically).

 With a tile language, this is really worth thinking about, since using tiles
 suggests ways to extend both the form and the meaning of the tiles.

My current thinking is that macros are *graphical*, not *source*
transformations.  You can create
your own tiles for the language which render into hygenic macros.
They are represented in source as simple message dispatch.  For
example, choosing a particularly ugly bit of JavaScript syntax:

var ForBlockMacro = imports.macros.ForBlockMacro;
var foo = function() {
 var i;
 ForBlockMacro(function() { i=0; },
   function() { return i  5; },
   function() { i+=1; },
   function() { /* body */ });
}

This is the underlying syntax for the macro.  But the ForBlockMacro
function (which is a first class object in JavaScript) can have an
asTile() method which returns a more attractive visual representation
in the tile editor; in fact, the representation could elide all the
'function' and 'return' nastiness of the raw syntax and display
(traditionally) as:

for ( i=0 ; i  5 ; i+=1 ) {
  /* body */
}

My current plan is to finess the multiple views issue (discussed in
3.4 of http://labs.oracle.com/self/papers/programming-as-experience.html)
by representing objects as 3d polyhedra.  The front view might be
the nice cleaned up tile macro, but you should be able to rotate the
tile to see the low level source, and then rotate it again to see the
object corresponding to the actual widget displaying the source, etc.
So, one object, many views.

I've built the current system on a very flexible operator precedence
grammar, so there's no reason I *couldn't* allow the user to flexibly
extend the base grammar.  But that increases the conceptual effort
necessary to understand the system -- I have to understand the
expanded language before I can understand the code I'm looking at.
The macro system I describe above has the nice property that you don't
*have* to understand the macro or the grammar of the new if statement.
 It's enough to look at the desugared version:

 ForBlockMacro(function() { i=0; },
   function() { return i  5; },
   function() { i+=1; },
   function() { /* body */ });

and the implementation of ForBlockMacro:

ForBlockMacro = function(initBlock, condBlock, incrBlock, bodyBlock) {
 initBlock();
 while (condBlock()) {
 bodyBlock();
 incrBlock();
 }
   };
   ForBlockMacro.asTile() = ;

This seems (to me) a preferable way of understanding what the new tile
does.  But I'm open to other ideas on this front.  (And yes,
JavaScript's syntax isn't lovely.  But I'm interested in what I can do
with what I've got.)
  --scott

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Re: [IAEP] Turtles All The Way Out

[C. Scott Ananian]

On Fri, May 20, 2011 at 2:28 PM, John Gilmore g...@toad.com wrote:
 separation.  This is why they never learn to modify the real programs
 that hide behind the fluffy interfaces on their real XO computers.

I hope to show you a system where the real program *is* the fluffy
interface (and vice versa).  I'm not at that point yet, but you've
correctly extracted the point of this particular research program.
  --scott

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Re: The next four weeks

[C. Scott Ananian]

On Tue, Apr 12, 2011 at 1:56 PM, C. Scott Ananian csc...@laptop.org wrote:
 On Mon, Apr 4, 2011 at 6:09 PM, C. Scott Ananian csc...@laptop.org wrote:
 I've posted a four week plan for XO-3 software exploration at
 http://cananian.livejournal.com/62667.html

 Briefly:
 April 4-8: Android
 April 11-15: Chrome/ChromeOS/NativeClient

 The report on the first week of work is now up at:
 http://cananian.livejournal.com/62756.html

The report on week two is now up, in three parts:

 * Sugar on Native Client (general observations)
  http://cananian.livejournal.com/63325.html
 * Comparing NaCl and Android, and some demos
  http://cananian.livejournal.com/63595.html
 * Next steps for the next month
  http://cananian.livejournal.com/63783.html

Bottom line: no major technical roadblocks. NaCl has the edge on web
integration, Android holds its market lead.
  --scott

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Re: XO-1.5 users: need your SD card data

[C. Scott Ananian]

Note that Quozl's version also works better on images created with
image-builder tools which delete files during the image creation
process (ie, on just about anything which involves mounting the
filesystem image during the image creation process; as opposed to
(say) squashfs, which is a read-only filesystem created all at once
from a filesystem tree at the very end).

Deleted files will leave 'dirty' blocks which are not zero but can
still be safely skipped.
 --scott

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Re: XO-1.5 users: need your SD card data

[C. Scott Ananian]

On Thu, Apr 14, 2011 at 10:10 PM, James Cameron qu...@laptop.org wrote:
 As an alternative, consider identifying the unused blocks in the
 filesystem, and avoid including them in the .zd file.  This would make
 it unnecessary to know whether the bits will be set or cleared by the
 card.  ext2, ext3, and ext4 care nothing for the bits in unused blocks.

This would also nicely finesse the problem that different cards may
erase to different values (0xFF vs 0x00).
  --scott

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Re: XO-1.75 - Flash, Java?

[C. Scott Ananian]

On Wed, Apr 13, 2011 at 9:16 PM, Alan Eliasen elia...@mindspring.com wrote:
   I considered it also a serious problem that the then-shipping
 configurations of the OLPC completely lacked fonts with glyphs for many
 languages (e.g. there were no fonts with Chinese or Japanese characters)
 so these languages could not be rendered in any application on the OLPC,
 including in the browser. This should probably be considered to be a bug
 in a supposedly-internationalized platform, and affects language
 learning, or even seeing what another language looks like.

The Chinese and Japanese fonts are *very* large.  I believe OLPC only
ships them to countries which need them, in order to make more space
for kids' stuff.
 --scott
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Re: The next four weeks

[C. Scott Ananian]

On Mon, Apr 4, 2011 at 6:09 PM, C. Scott Ananian csc...@laptop.org wrote:
 I've posted a four week plan for XO-3 software exploration at
 http://cananian.livejournal.com/62667.html

 Briefly:
 April 4-8: Android

The report on the first week of work is now up at:
http://cananian.livejournal.com/62756.html

Basically -- yes, I can see how Sugar-on-Android can be done.  No
major blockers, but the build chain and packaging issues will be an
initial annoyance.
 --scott
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Re: The next four weeks

[C. Scott Ananian]

2011/4/12 NoiseEHC noise...@freemail.hu:
 What I do not get is this: what is the goal?

An excellent educational experience on tablet devices, within the
resources of the current Sugar community.

 Having an environment running on Android which can run the same XO bundles
 which are run by XO-1.x?

Ideally, yes.  In practice, some porting will almost certainly be
required; the goal would be to minimize that work.

In addition, in the Android scenario, Sugar would gain the ability to
run educational activities written natively for the Android
environment which would provide capabilities currently missing from
Sugar -- for example, the Android Movie Studio activity.

 If the Sugar API has to be changed (adapted for some technical reason) would
 you fork all activities?

It may be possible to write activities such that they can run on
either platform.  TurtleArt has a number of ports, for example, but I
do not believe it has forked.  It's a little too early to make
definitive statements, but obviously there are many benefits to
avoiding unnecessary forks.

And, again, I have to remind folks that this is only *one* possible
forward path for Sugar-on-Tablets.  This week I am examining a
ChromeOS-based option.  http://cananian.livejournal.com/62667.html
describes the current plan of work, and there will be further
exploration of promising options after that.
  --scott
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Re: The next four weeks

[C. Scott Ananian]

On Tue, Apr 12, 2011 at 5:45 PM, Peter Robinson pbrobin...@gmail.com wrote:
 And, again, I have to remind folks that this is only *one* possible
 forward path for Sugar-on-Tablets.  This week I am examining a
 ChromeOS-based option.  http://cananian.livejournal.com/62667.html
 describes the current plan of work, and there will be further
 exploration of promising options after that.

 Out of interest is the meego tablet / touch interface on the to look
 at list as well?

Meego development has been quite turbulent.  The goal is to build on a
stable and reliable foundation, so that OLPC won't have to do as much
basic platform work.   It's not clear that meego will provide that, or
that meego will ever be a first-class citizen on ARM
(http://wiki.meego.com/ARM).

But meego's definitely on the list.  Just not as high priority at the moment.
 --scott
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Re: The next four weeks

[C. Scott Ananian]

Thanks for your links to the mailing list threads.  That's handy to
have at my fingertips.

I agree that the activities are key.  Transparent compatibility is
probably impossible, but I hope that porting the activities will not
be too hard.  Minimizing unnecessary API changes and writing a good
porting guide should go far.

The Journal and Portfolio are really important part of Walter's vision
of Sugar.  They will be system services, with strong enough
modularization to allow multiple competing implementations.  I know
how that will work in web/nativeclient model.  I'm not certain how
that works on Android yet; hopefully by the end of this week I'll have
some better ideas.
  --scott
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The next four weeks

[C. Scott Ananian]

I've posted a four week plan for XO-3 software exploration at
http://cananian.livejournal.com/62667.html

Briefly:
April 4-8: Android
April 11-15: Chrome/ChromeOS/NativeClient
April 18-22: Get down  dirty with mesh
April 25-29: Yanking legacy Sugar codebase into the future
May 2-6: in Uruguay to present results and discuss all this w/ Sugar
folks in person

I'll be posting more about each project as I dig into them; there are
also threads on IAEP where I've discussed all these topics before, so
they shouldn't come as too much of a surprise.

There are other ideas out there, and I'm not going to *finish* any of
these investigations in a single week.  Feel free to ask questions and
suggest other projects -- although please read the existing
discussions first if you can.  In order to actually get work done w/o
endless distraction, I'll probably try to avoid getting into lots of
details for projects other than the one I'm currently focusing on.
 --scott
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People to talk to

[C. Scott Ananian]

This is a corollary with my recent post on things to do -- here are
the people I've like to get OLPC talking/working more closely with.

Google teams:
 - ChromeOS (Ed has contact info already for the ChromeOS on ARM
project manager)
 - Android
 - NativeClient

Networking teams:
 - OLSRd (we've got good contacts, just need to reawake/nuture them)
 - 802.11s (cozybit and that community)
 - Universities interested in research and deployment of mesh networks

Miscellaneous:
 - JG is very excited about content-centric networking.  There's a
large NSF project around this; contact program leads.
 - Haptic technologies (wad and I have been chasing down some leads here)

Anyone have specific contacts for any of these areas, and/or want to
suggest other external teams we should be working with?
 --scott
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Re: Possible XO Graphics Optimization Technique

[C. Scott Ananian]

On Apr 1, 2011 11:03 AM, Samuel Greenfeld greenf...@laptop.org wrote:

 Hello all:

 As many of you are aware, work is being done to improve the graphics
performance of various XO laptop platforms.

 So in an attempt to improve things further, I looked into optimizing the
data Sugar sends to the video subsystem itself.

 I think I have made some improvements, and put up some samples of my Sugar
interface work at http://www.greenfeld.org/1April2011/ .  Feedback is
welcome.

 But while I have drastically reduced the amount of bandwidth required to
display the Sugar interface, I fear I have significantly increased the
amount of power required for optimal rendering.

Very nice work.  It looks like the sugarlabs website could use some better
markup. (Sidebar at the end would make it more readable.)
  --scott
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Re: Any restrictions or recommendations regarding SD cards?

[C. Scott Ananian]

On Thu, Mar 24, 2011 at 3:26 PM, Christoph Derndorfer
christoph.derndor...@gmail.com wrote:
 Hi all,
 the folks from the Austrian pilot project want to equip the XO-1s there with
 SD cards. Are there any restrictions wrt size, speed, etc. that they should
 be aware of when purchasing the SD cards? I'm particularly asking after
 reading James' mention of seeing more issues with newer cards and the XO-1
 power off bug.
 Or asked the other way 'round: Are there any particular cards or
 manufacturers which people can recommend?

My recommendation would be to get some samples and test them.  The
manufacturer's name doesn't really tell you much when it comes to SD
cards.

There are some numbers at http://wiki.laptop.org/go/NAND_Testing but
again, your results will vary.

More speed is always better, but class 4 isn't *necessarily* slower
than class 6, it all depends on what parts they had on the shelf
that day.  But it's probably worth looking for the fastest cards you
can afford.
  --scott

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Re: Mesh Potatos and OLPCs?

[C. Scott Ananian]

On Wed, Mar 23, 2011 at 9:30 PM, Peter Robinson pbrobin...@gmail.com wrote:
 On Wed, Mar 23, 2011 at 11:38 PM, John Gilmore g...@toad.com wrote:
 Meraki are also doing mesh related things with the APs etc.

 Its my understanding (not that I've had much time to play) that mesh
 has improved greatly over the last couple of years with developments
 like BATMAN which is now in the 2.6.38 mainline kernel. I suspect pure
 IPv6 might also assist with some of the problems seen with broadcast
 on mesh networks as they get larger simply due to its lack of it.

IPv6 isn't a magic bullet for mesh.  If anything, IPv6's reliance on
multicast for basic ARP-type stuff adds additional difficulties.

That's not to say that IPv6+mesh is impossible.  I'm just saying it
doesn't make things significantly *easier*.

I agree with Ed's contention in so far as I also haven't seen anyone
doing exactly what OLPC originally wanted to do.  I also agree with
Peter and Charles that Mesh has matured greatly in the past few years
(although the mature deployements are not exactly OLPC's use case).

I think the opportunity is there for either (a) someone to take the
mature meshes and push them the extra distance to work in OLPC's case
(mobile nodes, ideally IPv6, dynamic mesh configuration), or (b) OLPC
to rethink its deployments such that the mature mesh technologies are
more immediately applicable.  As one strawman proposal for (b), you
might consider making the school servers the mesh nodes, not the XOs.
As another strawman proposal for (b), you could flip a switch to
make an XO into a dedicated stationary mesh node -- and put it on a
pole in the middle of the neighborhood with a solar panel, say.
Either of these would be significantly different from the original
every child's machine also a mobile mesh node vision -- but might be
much closer to the mature deployed mesh technologies.
 --scott

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Re: 11.2.0 development build 14 released

[C. Scott Ananian]

On Mon, Mar 21, 2011 at 1:52 AM, C. Scott Ananian csc...@laptop.org wrote:
 On Mon, Mar 21, 2011 at 1:01 AM, Daniel Drake d...@laptop.org wrote:
 On 19 March 2011 17:16, Daniel Drake d...@laptop.org wrote:
 updates.laptop.org now offers this stream. Instructions are on the
 11.2.0 page above.

 Unfortunately this doesn't work.

 Files such as /etc/shadow and /etc/gshadow are now installed from
 Fedora with permissions 000.

 rsyncd on updates.laptop.org runs as non-root, hence cannot read these files:
 rsync: send_files failed to open root/etc/gshadow (in
 build-11.2.0_xo1.5-14): Permission denied (13)

 We could fix this by making these files have permissions 400 in the
 image, or by making rsyncd run as root on updates.laptop.org.

 Scott, any thoughts?

 I used to run rsyncd inside fakeroot, which solved these problems
 neatly.  There's also a --fake-super option to rsync which can work.
 Or you can just run rsync as root.

http://dev.laptop.org/git/users/cscott/upgrade-server/tree/upserv.py
used fakeroot.
The --fake-super option was added after upserv was written; it's
probably a better solution now.
I don't know what's actually running on updates.laptop.org these days.
  --scott

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Re: Updating olpc-boot-anim for a 10.1.3 build with minimum fuss

[C. Scott Ananian]

Originally you could override by putting frames in ~/.bootanim.
  http://wiki.laptop.org/go/Tweaking_the_boot_animation
Don't know if that's still the case.
 --scott

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Re: Discovering the XOs local timezone in a bash script

[C. Scott Ananian]

I apologize; I think the code that sets timezone correctly might
have been code I wrote for litl, not OLPC.
  --scott

On Sunday, March 13, 2011, Daniel Drake d...@laptop.org wrote:
 On 13 March 2011 03:21, Samuel Greenfeld greenf...@laptop.org wrote:
 Sugar reports only relative times in its core GUI, so I don't know how
 common it is for deployments or other users to actually change this
 setting.  Setting a time zone other than UTC with 10.1.3 and prior may
 also expose a flaw where the offset is repetitively applied every
 reboot, shifting the clock.

 Just to remove any doubt..
 Setting the time zone from the control panel doesn't have any adverse
 effects such as the clock shift described above. This is is because
 sugar's time zone is isolated from the rest of the system as described
 here.

 Setting a different timezone on the system level will cause problems
 on existing builds, but there is no UI for this, and this is fixed in
 11.2.0 (with a UI now available via olpc-os-builder configuration
 setting).

 Daniel
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Re: Memory replacement

[C. Scott Ananian]

On Sun, Mar 13, 2011 at 8:57 AM, Andrei Warkentin andr...@motorola.com wrote:
 Sorry to butt in, I think I'm missing most of the context
 herenevertheless... I'm curious, ignoring outer packaging and
 product names, if you look at cards with the same CID (i.e. same
 manfid/oemid/date/firmware and hw rev), do you get same performance
 characteristics?

No.
 --scott

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Re: Memory replacement

[C. Scott Ananian]

On Sun, Mar 13, 2011 at 1:00 PM, C. Scott Ananian csc...@laptop.org wrote:
 On Sun, Mar 13, 2011 at 8:57 AM, Andrei Warkentin andr...@motorola.com 
 wrote:
 Sorry to butt in, I think I'm missing most of the context
 herenevertheless... I'm curious, ignoring outer packaging and
 product names, if you look at cards with the same CID (i.e. same
 manfid/oemid/date/firmware and hw rev), do you get same performance
 characteristics?

 No.

To elaborate: see bunnie's blog post (cited above) on how the CID is
often forged or wrong.  I've also personally witnessed a
manufacturer's rep come to the factory floor to reprogram a compact
flash card's internal microcontroller with new firmware.  This did not
update any externally visible information reported by the chip.  I had
to convince the manufacturer to leave their proprietary hardware on
the factory floor in order to be able to verify that future units
would have the correct firmware.  (Granted, this was not an MMC unit,
but I would be surprised if MMC vendors were significantly different
in this regard.)

If you've spent any time working with Chinese/Taiwanese OEMs, you will
notice that version control methodologies are (in general)
disappointingly lax.
 --scott

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Re: Discovering the XOs local timezone in a bash script

[C. Scott Ananian]

On Sun, Mar 13, 2011 at 1:04 PM, Sascha Silbe si...@activitycentral.com wrote:
 Excerpts from C. Scott Ananian's message of Sun Mar 13 16:41:36 +0100 2011:

 I apologize; I think the code that sets timezone correctly might
 have been code I wrote for litl, not OLPC.

 No problem. Do you remember how it worked at Litl? Did you manipulate
 /etc/timezone directly or using a distro specific tool?

We read the list of time zones from /usr/share/zoneinfo/zone.tab in
the GUI code, and set the time and time zone by calling /sbin/hwclock
and manipulating /etc/localtime and /etc/timezone directly in what I
believe was a dbus system service running as root.  The dbus service
was about 70 lines of g-o-i javascript.
  --scott
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Re: Memory replacement

[C. Scott Ananian]

Canonical related blog post: http://www.bunniestudios.com/blog/?p=918

Mandatory reading for anyone who has to deal with flash memory.
 --scott

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Re: Memory replacement

[C. Scott Ananian]

On Sat, Mar 12, 2011 at 5:51 PM, Arnd Bergmann a...@arndb.de wrote:
 I've had four cards with a Sandisk label that had unusual characteristics
 and manufacturer/OEM IDs that refer to other companies, three Samsung (SM)
 and one unknown (BE, possibly lexar). In all cases, the Sandisk support
 has confirmed from photos that the cards are definitely fake. They also

Please see the blog post I cited in the email immediately prior to
yours, which discusses this situation precisely.  Often the cards are
not actually fake -- they may even be produced on the exact same
equipment as the usual cards, but off the books during hours when
the factory is officially closed.  This sort of thing is very very
widespread, and fakes can come even via official distribution
channels.  (Discussed in bunnie's post.)

 However, they have apparently managed to make them work well
 for random access by using some erase blocks as SLC (writing only
 the pages that carry the most significant bit in each cell) and
 by doing log structured writes in there, something that apparently
 others have not figured out yet. Also, as I mentioned, they
 consistenly use a relatively large number of open erase blocks.
 I've measured both effects on SD cards and USB sticks.

You've been lucky.

 I believe you can get this level of sophistication only from
 companies that make the nand flash, the controller and the card:
 Sandisk, Samsung and Toshiba.
 Other brands that just get the controllers and the flash chips
 from whoever sells them cheaply (kingston, adata, panasonic,
 transcend, ...) apparently don't get the really good stuff.

You're giving the OEMs too much credit.  As John says, unless you
arrange for a special SKU, even the first source companies will give
you whatever they've got cheap that day.

 How we deal with this is constant testing and getting notification from
 the manufacturer that they are changing the internals (unfortunately,
 we aren't willing to pay the premium to have a special SKU).

 Do you have test results somewhere publically available? We are currently
 discussing adding some tweaks to the linux mmc drivers to detect cards
 with certain features, and to do some optimizations in the block layer
 for common ones.

http://wiki.laptop.org/go/NAND_Testing

But the testing wad is talking about is really *on the factory floor*:
 Regular sampling of chips as they come into the factory to ensure
that the chips *you are actually about to put into the XOs* are
consistent.  Relying on manufacturing data reported by the chips is
not reliable.
  --scott

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Re: Discovering the XOs local timezone in a bash script

[C. Scott Ananian]

Last I knew we used standard Linux conventions for timezones and sugar
called the standard Linux commands (via sudo) to set the timezone.
But that should make 'date' report the correct local time (unless you
use '-u') so maybe someone broke that sometime in the past two years.

Check /etc/timezone?
 --scott

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Re: XO-1 developer key does not work

[C. Scott Ananian]

Posting your machine's serial number as well as then contents of your
develop.sig might help; your developer key might be malformed or
correspond to a different XO than the one you are trying to use it on.

You can also try the collection key method, as one more check on the
process by which you are generating the developer key.
  --Scott

On Friday, March 11, 2011, Sridhar Dhanapalan srid...@laptop.org.au wrote:
 I am trying to put a permanent developer key on an XO-1. I have been
 following the steps at
 http://wiki.laptop.org/go/Activation_and_developer_keys

 First, I created the key using devkey.html. Then I copied develop.sig
 to /security on the XO. After rebooting, I still see a wp tag in
 /ofw/mfg-data.

 Then I copied develop.sig to /security to a USB drive. Turning the XO
 on with the drive plugged in makes no difference. If I hold down the
 tick key while turning on, I get the messages:

   trying disk:\security\develop.sig
   Devel key  No matching records
   ...
   Trying nand:\security\develop.sig
   Devel key  No matching records

 I tried several FAT32-formatted USB drives, including one that I have
 used to upgrade to the latest signed firmware.

 Can anyone help out?

 Thanks,
 Sridhar
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Re: [OLPC-AU] XO-1 developer key does not work

[C. Scott Ananian]

On Sat, Mar 12, 2011 at 2:16 AM, Mikus Grinbergs mi...@bga.com wrote:
 why am I getting different readings for each method?

 My guess is that file /home/.devkey.html was copied in from some other
 system, and shows the serial number and UUID of the copied-from system.

It would be interesting to investigate how /home/.devkey.html got onto
the machine -- ie, what build you used, and how you installed it onto
the device -- in order to prevent this problem from recurring.

 I myself would trust the collection key values.

yup.
 --scott

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Re: Require .olpc in rpms in ~/public_rpms/F14?

[C. Scott Ananian]

FWIW, the original intent was *only* to allow SRPMS in the dropbox; we were
going to explicitly rebuild the RPMs from the SRPMS in mock and use only the
built RPMs.  In addition to ensuring compliance with licensing provisions,
this was also intended as a developer aid: at the time, it was often easier
to generate a correct patched SRPM from the source than it was to create an
appropriate and up-to-date mock environment for the build, and often
developer RPMs were built in subtly-incompatible environments.  I don't know
if those concerns are still valid at the present time.

Like many things from long ago, the build from SRPM feature was incomplete
when it lost its developers.  It might be the proper time to resurrect it,
although perhaps having RPMs which don't match the SRPM isn't a problem any
more.
  --scott

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Content-Centric Networking.

[C. Scott Ananian]

Recapping for the list: Jim Gettys sent me a pair of papers to read
yesterday, both linked from
http://www.ccnx.org/content/content-centric-networking-resources

1) V. Jacobson, D. K. Smetters, J. D. Thornton, M. F. Plass, N. H. Briggs,
R. L. Braynard (PARC) Networking Named Content, CoNEXT 2009, Rome, December,
2009.
2) V. Jacobson, D. K. Smetters, N. H. Briggs, M. F. Plass, P. Stewart, J. D.
Thornton, R. L. Braynard, VoCCN: Voice Over Content-Centric Networks, ReArch
'09, Rome, December, 2009.

This is very interesting work, and offers an alternative to
http://wiki.laptop.org/go/Network_principles

In my mind, the best reason to continue to use DNS and IP routing to locate
resources (as in the Network Principles document) is that deployments
understand them.  However, the CCNx approach could offer significant
bandwidth benefits, and potentially works better in the kids go home from
school case (the Network Principles document requires IPv6 tunnels to solve
this mobility problem).

I think the CCNx ideas would be worth exploring, but OLPC would need active
participation from the PARC CCNx folks.  OLPC role would be
integrator/deployer, *not* developer or researcher.

So, with that in mind, the greatest missing piece I see is an HTTP gateway.

Here's how it would work:  CCNx content bundles with a specially-formed name
(like http/url/here) would get routed by specially-aware content routers
over legacy HTTP.  The contents, once fetched, would be stored in the CCNx
network like all other content, making it a big web cache.  Running such a
CCNx gateway on the school server would turn it into the web cache we've
always dreamed of (and which perhaps has been implemented in the past two
years?).   This would let all of the laptops talk pure CCNx to each other,
without losing web access, and make the web behave better when machines are
disconnected.

For bonus points, the CCNx routers would use something like rproxy (
http://rproxy.samba.org/doc/protocol/protocol.html) when searching for
content from other CCNx routers, so that slightly changing content such as
is found more typically on the web is still highly cacheable, and we get
even more bandwidth improvement.

Both rproxy and the HTTP gateway are development projects; they're probably
even research projects, since it's not immediately clear how HTTP's caching
semantics (which need to be honored) translate into the CCNx namespace.  I
don't think it's a good idea for OLPC to do research projects, but if Van
and his team are enthusiastic about collaboration, I'd hope that OLPC would
be willing to integrate and deploy his ideas.  The win for OLPC would be
network bandwidth, which is a huge deal for the developing world; with
solutions to some resource discoverability issues a secondary
consideration.

Note that the two papers I've read so far don't really address the resource
discovery and naming issue.  They make some suggestive remarks, such as We
are also developing higher level name discovery mechanisms that are more
efficient for exploring large name spaces (Networking Named Content, page
4).  That's another area of concern for me.  As we learned the hard way,
just finding your friends and classmates in a large school can be a
surprisingly difficult problem, and CCNx's reliance on multicast with a
casual reference to standard multicast suppression techniques (Networking
Named Content, page 3) causes me concern.  But I'm sure OLPC would be more
than willing to provide the test cases if they are interesting in proving
that their name-discovery stuff actually works in the field.  So,
secondarily to the HTTP gateway, I would suggest the ol' Journal as a
research area they might like to explore: a collection of ~100 machines,
each of which has a (unique?) name and a collection of documents sorted by
date.  The task is to efficiently enumerate your friends or classmates, and
then look through their shared documents.  Ideally this would work even if
some of your friends (and their documents) aren't currently in class,
assuming other students have cached the relevant information.

(In addition, I would add an indirection layer: my best ideas for solving
the document collaboration problem involve the notions of borrowing vs
copying.  So person A can borrow some document, make edits (possibly
with others) and then return the borrowed document to the original owner.
 So when you request document A from friend X, the response might be friend
Y is currently borrowing it.  This might involve another request to friend
Y, with a different document name -- or it might involve friend Y
publishing a document in friend X's namespace.  I'd be very interested in
hearing the CCNx way to approach this problem.  The goal is to simplify
the multi-editor versioning problem by ensuring that there is exactly one
owner at any given time who is responsible for serializing edits.)

So, bottom line: very interesting work.  Offers some benefits even in an
isolated my CCNx network is just 

Re: Proposal for new frozen repositories server

[C. Scott Ananian]

On Sun, Feb 6, 2011 at 7:29 AM, Daniel Drake d...@laptop.org wrote:
 mock.laptop.org, our server for frozen packages i.e. a clone of the
 latest Fedora and OLPC RPMs frozen for each software release, is out
 of disk space and somewhat unloved, and I'd like to use the
 opportunity to make some changes to the system.

 In a sentence, the changes are: Repositories which are essentially
 unmodified by OLPC are moved out of revision control, and OLPC-local
 repositories are moved from being unrelated branches in a
 huge/old/long-living git repository into their own individual,
 short-lived git repositories.

 Full details here:
 http://wiki.laptop.org/go/User:DanielDrake/NewMockProposal

 Comments welcome. I'm looking to refine the proposal and implement it
 within the next few weeks

Why not just add more disk space?  Disk space is cheap.  Or archive
the older parts of the repo.

The benefit to version controlling even the non-OLPC packages is that
the repo contains a *complete* snapshot of all the bits that went into
a particular build.  This protects against upstream reorganizing their
repos, or cleaning old packages, or changing their package manager,
etc, etc.  It makes builds 100% reproducible at any point in the
future (or at least that was the point).  Removing any packages from
the repo would pretty much defeat the whole purpose.

If disk space really is a problem, one alternative is to make release
candidate builds on a branch, and only merge released builds to
master.  Then you can prune the branches with git to free up disk
space, while still ensuring that you have all the bits related to
released builds.  But really -- why not more disk?  [I understand
there are parts of mock which are non-ideal, but the essential saving
all the bits part isn't one of them. IMHO.]
  --scott

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Re: XO-1.75 A2 information

[C. Scott Ananian]

On Sun, Jan 9, 2011 at 6:02 PM, Carlos Nazareno object...@gmail.com wrote:
 Accelerometer?

 Sweet! :)

It looks like the XO-1.75 has the LIS33xx, which is roughly the same
accelerometer as used in the iPhone, Android phones, etc.

Our ODM suggested replacing our LIS33DH with an accelerometer from
Kionix (we went with the KXTE9; it turned out when we tested with
games we didn't need more than 6-bit resolution, but Kionix also has
high-resolution devices) because ST microelectronics was having
leadtime issues with the LISxx accelerometers.  I think the Kionix
solution saved a bit of BOM cost, too.

I don't know if that's a good second-source alternative for OLPC or
not, but it might be worth some investigation.
  --scott

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Re: Looking for startup sound recording

[C. Scott Ananian]

On Tue, Dec 7, 2010 at 12:04 AM, James Cameron qu...@laptop.org wrote:
 (You'll notice that on a good sound system it is quite different to
 playback on an XO ... it takes a bit of equalisation to reproduce the XO
 speakers.)

The converse, actually.  The sound file was extensively EQ'd so that
it is *accurate* when played on an XO's speakers.  Playback via other
output devices doesn't correctly reproduce the Edge's performance.
  --scott

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Re: Firmware update

[C. Scott Ananian]

On Wed, Nov 24, 2010 at 5:49 PM, Daniel Drake d...@laptop.org wrote:
 On 24 November 2010 22:40, Kevin Gordon kgordon...@gmail.com wrote:
 Is this recommendation against yum and rpm for all software, or just the
 oplc repo packages, the kernel and the firmware?  I'm certainly happy doing
 just safe builds for the core.

 To avoid all corner cases it the recommendation really needs to be 
 everything
 In reality, you'll probably get away with it, especially because
 you're only really working with added packages in your deployment (not
 upgrading ones that are already installed).

 Some of the resultant problems will also not affect small deployments
 like yours. For example, one side effect is that olpc-update pristine
 (efficient) updates stop working as soon as you make any filesystem
 modifications like this. Another side effect is that your
 custom-installed packages will magically disappear after an
 olpc-update upgrade (which in a real deployment would happen without
 you even knowing).

 But in a small deployment like yours, touching each laptop for updates
 is probably more sensible than the knowledge and infrastructure
 investment needed for hands-off olpc-update, so you aren't affected.

 However, as part of our 'refresh' stick when we wipe and install a new
 signed build, we generally also include the necessary rpm's for cheese and a
 couple of other utilities that are locally installed from the USB stick
 using a bash script; or, for the Vernier software dependencies, the
 dependent rpm's are installed by means of a python script.  However, they
 are rpm's and they are downloaded onto the stick (the first time) using yum,
 and they are then installed from the stick using --localinstall from the
 stick.

 You probably won't see any problem with this collection of changes.
 Nevertheless, at the SF summit I started showing Adam the correct
 way to do this: building a custom OS image with those customizations
 already included. We didn't have time to completely finish it, but he
 picked it up quickly and could probably finish it with a little effort
 (and perhaps a couple of mails to this list).

At one point Michael and I also had a side-loading mechanism
implemented -- if you put your target RPMs in some directory in
/home/olpc -- I think it was ~/.rpms -- then they'd automatically get
re-installed after olpc-update.  That was (at the time) the preferred
mechanism for adding a few packages persistently to a build.

Assuming this mechanism hasn't code-rotted, this is a nice
intermediate step: less work than rolling an entire new build, and
relatively easy to accomodate new upstream builds without
disruption.
  --scott

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Re: XO-1.5 audio input DC mode

[C. Scott Ananian]

On Wed, Nov 24, 2010 at 6:52 AM, Sascha Silbe
sascha-ml-reply-to-201...@silbe.org wrote:
 2. The voltage I see with bias off is probably generated internally by
   the codec chip. [...]
   Unless someone finds a magic way to disable this from the digital
   side of the chip (which I doubt), we'll have to cope with it. This
   means that we need an external buffer circuit in order to prevent the
   XO-1.5 from feeding voltage back into the measured circuit.

What is the impedance of your input?  What's the capacitance?

I can see getting some leakage current into a high-impedance
high-capacitance circuit, but for most purposes this shouldn't really
be a problem.
 --scott

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Re: SD card unpartitioned space -- used for swap?

[C. Scott Ananian]

Assuming OLPC isn't using TRIM support on the SD cards, writes to the
swap space are indistinguishable from writes to any other space on the
card.  That means that writes to the swap partition could
potentially corrupt other data on the card, especially if it occurs
less than 30s before removal of power (or whatever that evil keepout
time is).

From my recent experience, I wouldn't be too worried about swap space
wearing out the SD card, as we used to -- but that's not to say it's
100% safe, all reads and writes are risky to some degree.  We've seen
up to 60s delays on reads from flash as well, you might consider how
that might affect perceived performance.

FWIW, litl also uses a no-swap-space linux setup.  We haven't actually
had any problems with it; bugs I thought I could pin on
low-memory/no-swap issues turned out to actually be bugs in the Atom
page table hardware (!) which were exacerbated when lots of page table
operations were done -- in our case, GPU-heavy tasks triggered the bug
just as well.  Our superstitions about OLPC's no-swap configuration
may well prove to be similarly unfounded.
  --scott

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Re: SD card unpartitioned space -- used for swap?

[C. Scott Ananian]

As my own clarification: I wasn't dismissing possible performance
improvements (of any kind).  I was just commenting on the old lockup
bugs, saying this might not actually be related to no-swap-space,
although it's possible memory pressure exacerbates the problem.  For
performance issues, you have to balance against the risks.  If it
enables you to run ooo, maybe it's worth it.  It seems you might also
be introducing a configuration management issue, though, where only
some units with a given SKU can run (say) OOo.
  --scott

On Monday, November 22, 2010, Daniel Drake d...@laptop.org wrote:
 On 22 November 2010 16:41, Martin Langhoff martin.langh...@gmail.com wrote:
 Just to clarify -- side-to-side comparison in the past have shown a
 significant improvement. We did get a specially bad-behaving kernel in
 our F7 builds in that regard, but even F9 builds have shown it to be
 better.

 That was an XO-1 comparison though.
 I haven't heard of similar problems existing for XO-1.5, but my field
 experience there is much less. Are there known situations where adding
 swap actually helps?

 Another thing to consider would be the current series of patches going
 into Linux that improve interactivity under high CPU/memory pressure.
 Certainly candidates for inclusion if we can briefly show their value.

 Daniel


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Re: SD card unpartitioned space -- used for swap?

[C. Scott Ananian]

On Mon, Nov 22, 2010 at 6:43 PM, Mikus Grinbergs mi...@bga.com wrote:
 If indistinguishable is true, then there is as much wear to the SD
 card from one file-block written as there is from one swap-block
 written.

Yes.

  I have no measurements whatsoever - but my gut feel is that
 the majority of my SD card writes are for file-blocks.  If that happens
 to be the case, then writes to swap space are a minor wear contributor.

Measurements are always helpful.

 Also, I'm not familiar with evil keepout time.  But note that on the
 new XO-1 F14 build, the shutdown time-lapse is only a few seconds.
 If actually 30s are needed to keep the SD circuitry happy, perhaps a
 delay (and a Release Notes explanation) should be added to the OLPC.

This is an issue with particular brands of SD cards.  It's not an XO
issue, per se.

 To advance the discussion, collecting a quantitative measure
 of average swap writes per day given some usage profile would let
 you more-or-less rigorously determine whether swap was 'safe' over the
 5 year expected lifetime of the device.

 Note:  I'm using an external SD card.  So if it fails before the OLPC
 itself fails, I can at reasonable expense replace this swap device -- I
 don't have to plan for a definite wear lifetime.

Are you making regular backups?

 If you started
 collecting/recording total data written to your swap partition, I'd be
 very interested to hear (in a month or so) what your numbers were.

 I'm NOT into instrumentation.  Please help me in locating software that
 will collect the number of swap (and file) writes to a physical device
 -- but it must be software that is simple_for_me_to_install_on_OLPC.
 [For persistence, the output of that software needs to go to the SD.]

The contents of /proc/diskstats seem to contain the interesting info.
http://www.linuxquestions.org/questions/suse-novell-60/interpreting-proc-diskstats-360350/
describes their interpretation.  A user-friendly script would probably
live in /etc/init.d and record the relevant information from
/proc/diskstats at shutdown time.
  --scott

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Re: Notes on conventional desktop tools

[C. Scott Ananian]

On Thu, Nov 18, 2010 at 2:48 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
  - Flash pays a hefty price for its refusal to use Xv. Don't install 
 pulseaudio.
  - Skype 2.0.0.72 works reasonably well once you set the right
 microphone input. Latest Skype (2.1.0.81) doesn't play well with our
 ALSA implementation. We aren't alone in this, various chipsets/drivers
 are affected similarly -- your voice is distorted into a growling
 mess, see https://jira.skype.com/browse/SCL-638 -- someone with
 serious alsa trickery and magic may be able to massage .asoundrc to
 work around the issue, I could not. This is recent - previous release
 2.1.0.47 has good audio but video is corrupt.

I think you'll have more success with the latest skype using pulseaudio.

Yes, pulseaudio is awful.  But it's what's being adopted upstream.
Pain now == less pain later.  (But you probably want to use the
pulseaudio plugin called idle something or other (IIRC) to close the
audio device when it's not being used, otherwise your indicator light
will be stuck on.
  --scott

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Re: Notes on conventional desktop tools

[C. Scott Ananian]

On Thu, Nov 18, 2010 at 3:41 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
 On Thu, Nov 18, 2010 at 3:08 PM, C. Scott Ananian csc...@laptop.org wrote:
 I think you'll have more success with the latest skype using pulseaudio.

 No need for speculation. I can tell you: in general terms, F11
 pulseaudio ain't a good one. And for whatever reason, this pulseaudio
 does not play ball with our alsa drivers.

 PA proponents should hop on the F14 builds and push, tweak,
 bastardize, abuse, patch and report :-)

Perhaps you are mistaking me for a PA proponent.  ;-)  I just know
which way the wind is blowing.
  --scott

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Fwd: Upgrading a _very_ old OLPC

[C. Scott Ananian]

-- Forwarded message --
From: Krishnan R.S. rskrish...@hotmail.com
Date: Wed, Nov 17, 2010 at 2:48 AM
Subject: Upgrading a _very_ old OLPC
To: csc...@laptop.org


Hello,
   I managed to get my hands on a very old OLPC XO laptop for my
daughter. I've been trying, unsuccessfully, to upgrade the OS to
something current. The main issues are:

My image has no olpc-update
I tried to follow the wiki instruction to update olpc-update - alas
that leads to more issues about missing python2.5
I tried to install python using apt/deb/dpkg but all of these fail
since the apt/deb/dpkg tools are missing :(
Looking at /etc/issue - I see build 417 - and some messages that look
like errors kernel \r \m  :) so maybe I have a pre-alpha build
:)

So ... I'm somewhat at a loss as to what my next steps are. My
daughter seems pretty excited with the device and enjoys the paint
application. I'd like to get a more recent build so she can use the
newer apps/toos.
Can you point me in the right direction ? Or am I wasting my time
trying to do the impossible?
Thanks,
Krishnan
+1-415-606-3069
--
Krishnan Subramaniam
rskrish...@hotmail.com




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Re: XO-1.5 audio input DC mode

[C. Scott Ananian]

As a wild stab at a first guess, it sounds like a software problem to
me -- seems like xoscope is not successfully turning off either the
bias voltage or the decoupling capacitor (high pass filter).  Perhaps
a silent failure of some sort?
  --scott

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Re: XO-1.5 audio input DC mode

[C. Scott Ananian]

On Wed, Nov 17, 2010 at 2:46 PM, C. Scott Ananian csc...@laptop.org wrote:
 As a wild stab at a first guess, it sounds like a software problem to
 me -- seems like xoscope is not successfully turning off either the
 bias voltage or the decoupling capacitor (high pass filter).  Perhaps
 a silent failure of some sort?

If you've got access to a signal generator (or another machine with a
sound card), feeding in a 1kHz square wave with an offset (say 0 off,
1V on) is probably a better diagnostic than using your potentiometer.
If my wild guess is correct, then you should see a characteristically
rounded square wave with no offset.  Then you could poke at the
software until (a) the rounding goes away, and (b) you see the offset
you expect, which would indicate that the decoupling capacitor has
successfully been switched out of the circuit.
  --scott

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Re: Re: XO-1.75 microphone socket

[C. Scott Ananian]

On Tue, Nov 16, 2010 at 11:38 AM, Walter Bender walter.ben...@gmail.com wrote:
 On Tue, Nov 16, 2010 at 11:19 AM, C. Scott Ananian csc...@laptop.org wrote:
 On Mon, Nov 15, 2010 at 4:19 PM,  fors...@ozonline.com.au wrote:
 Just make sure you keep in mind the difference between the specification 
 and what is likely to be acceptable.  One value is better suited to 
 personal tinkering, the other to widespread propagation.

 Good point. As background to my questions Turtle Art 103 now supports 
 sensor input.
 http://wiki.sugarlabs.org/go/Activities/TurtleArt/Using_Turtle_Art_Sensors

 As the specification stands, no teacher is going to conduct science 
 experiments with external voltages. If the specification is changed to +-9v 
 then they will have the confidence to conduct experiments with caution.

 Why not use 1.5V alkaline cells?  Or measure voltage from a lemon
 battery?  I can think of any number of safe experiments.

 Why not indeed. See
 http://wiki.sugarlabs.org/go/Activities/TurtleArt/Using_Turtle_Art_Sensors#Lemon_battery

Right.  You can also do quite a lot of useful experiments using the
built-in 2V bias.   I'm not sure exactly what the problem is -- maybe
Tony can offer a more precise objection?  Perhaps he feels there needs
to be more guidance given on how teachers can construct fool proof
sensor experiments that are minimally dangerous to hardware, even if
the teacher isn't watching every kid every minute?
  --scott

ps. my rule of thumb would be don't involve an external battery more
powerful than a lemon  -- as I understand the protection circuits,
there's no way you can connect the internal bias voltage coming from
the microphone jack in a way that would damage the input.  You can
construct a lot of experiments (ie, most on the Turtle Art Sensors
page) which are thus guaranteed safe, even if kids make mistakes on
an XO-1.5/XO-1.75.  But the measuring AC amps example should be
moved to a separate only with supervision and adequate care page.
(Maybe also the Generating electricity example also, although it
would take a lot of turns of wire, a pretty strong magnet, and very
vigorous motion to exceed 9V.)  And the Lemon battery and
generating electricity examples should additionally be warned
against on the XO-1 --- maybe also the burglar alarm, depending on
whether the XO-1 is always safe if its inputs are shorted.

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Re: XO-1.75 progress

[C. Scott Ananian]

Hey, that looks a lot like the conference rooms *I've* been spending
weeks in! ;-)
 --scott

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Re: Synaptics driver on XO-1.5 hw?

[C. Scott Ananian]

On Thu, Oct 28, 2010 at 11:01 PM, Daniel Drake d...@laptop.org wrote:
 On 28 October 2010 15:54, Martin Langhoff martin.langh...@gmail.com wrote:
 On XO-1, we have a long painful history with synaptics and the EC,
 that's led to it being disabled. Instead we use the PS2 protocol.

 I just realised that we still do that on XO-1.5 on F11 and F14 builds,
 and can't find commentary from anyone trying anything different.

 Are there reasons to think Synaptics may now work?

 As far as I know there is still no explanation nor diagnosis for the
 super-strange EC behaviour in this mode. I don't know if anyone has

IIRC (and it's been a long time, so don't trust me on this) the
Synaptics PS/2 protocol involves more 'context' than the standard
mouse packet format, making it more likely that dropped PS/2 bytes
could lead to desynchronization (and Bad Mousing).  If the underlying
PS/2 bus code is more reliable on XO-1.5, I'd expect that Synaptics
might be fine again.

FWIW, careful about the distinction between the Synaptics PS/2
protocol (since there are USB versions), the Synaptics driver in the
kernel, which converts that protocol to evdev, and the Synaptics X
driver which is actually hardware agnostic and just translate generic
evdev messages into X events, handling edge scrolling and other nice
touchpad features. (Although on non-evdev platforms I understand that
the Synaptics X driver does contain code to parse the Synaptics
PS/2 protocol.)

I highly recommend using the Synaptics X driver.  I don't know enough
about the XO-1.5 hardware to say whether you should be using the
Synaptics PS/2 protocol.
  --scott

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Re: Aggressive suspend vs NM/DHCP

[C. Scott Ananian]

On Wed, Oct 20, 2010 at 5:55 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
 The right fix is just what we wanna do for the upstream dev branch,
 for the next cycle.

Sigh.
  --scott

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Forwarded developer key request (was Fwd: Internal Server Error)

[C. Scott Ananian]

Forwarded conversation
Subject: Internal Server Error


From: *Pavel Stržínek* strzi...@edhouse.cz
Date: 2010/9/11
To: csc...@laptop.org


Hello Scott

I'm trying to apply for a developer key for OLPC v1 from Browser
activity right on XO device but I'm getting Internal Server Error
message.

Is it still possible to get the developer key? Is the error just a
temporary situation on server or some problem on my device?

Thank you for your answers,

Regards

Pavel Strzinek






--
From: *Pavel Stržínek* strzi...@edhouse.cz
Date: 2010/9/11
To: csc...@laptop.org


Additional XO info:

serial number: CSN74701271
Build: 802
Sugar: 0.82.1
Firmware: Q2E41

Pavel Strzinek




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Re: [IAEP] Mesh Dreams = OLSR

[C. Scott Ananian]

I'm not 100% certain we've pulled in members of the OLSR mailing lists
on this thread yet.

But they've actually got a number of very impressive *real world*
demonstrations of OLSRd in the wild.  You'll have to search the devel@
archives for 'olsr' to find the emails I sent years ago with all the
details.

Granted, I don't know that they've demonstrated the software scaling
out to distributed notes *and* in to 100 laptops in a single room w/o
any manual tweaking.  They can best tell you about that themselves.

But OLSR is a much more appropriate and much less pixie dust
solution than 802.11s ever was/is/will be.

I think the primary challenge is social -- isn't it always?  The OLSRd
guys have to get passionate about making their stuff work on XOs, and
enough deployments have to be adventuresome (and desperate) enough to
give them a testbed to iron out all the kinks.

But I think it's a worthwhile management challenge for someone to
attempt.  Because what's needed is leadership, managing the resources,
linking person A to person B, driving it to release/ship, and a little
bit of inspiring the troops.  The technical challenges are much less
hard.

(And it's probably an outside OLPC project, at least initially,
because OLPC can't afford to devote any resources to it.)
  --scott

ps. technical challenges: making it bulletproof and brainless,
seamless scalability from lots of laptops in a tight space to a few
laptops spread out, and (eventually) processor-independent operation
on the marvel microcontroller to allow sustaining the mesh at very low
power levels.
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Re: SD/MMC cards, a year later

[C. Scott Ananian]

On Thu, Aug 19, 2010 at 11:24 AM, John Watlington w...@laptop.org wrote:
 Our experiment with SD/MMC cards as main storage continues.

FWIW, I'm about two weeks into failure testing of 4G MLC compact flash
from a couple of vendors.  I'll update the list when one or both of
them kick the bucket. Is OLPC looking at SD rather than CF for price,
speed, form factor, or other reasons?
 --scott

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Re: [IAEP] Redesigning: Library, Read, Get-Books, and Content bundles

[C. Scott Ananian]

On Tue, Jul 20, 2010 at 2:33 PM, Reuben K. Caron reu...@laptop.org wrote:
 deployments that would like to install content bundles. They package
 these files into .xol packages and these packages get installed into
 the Library, which is contained on the left hand side of the Browse
 activity. Yes, you read that correctly...the BROWSE activity, an
 activity intended for online exploration is used to view offline
 content. Every deployment that I have shown this to has found it very
 unintuitive. Consider another example: You want to use Get-Books to

The original goal was to blur the boundary between offline and online
as much as possible.  You would have a large-ish cache of online
material available offline -- including not only your textbooks, but
also many other web sites or educational resources.  Updating a
textbook would be as easy as updating the online source of that
textbook, and the offline copy would get updated from that.  Surfing
while offline to a page which was not available in the offline cache
would create a request for that content, which would be fetched when
you are next online, or added to a queue for your teacher to fetch
next time they travelled to a place with internet access.

This is a pretty straightforward extension of the wwwoffle program,
but the necessary tuits to integrate all the pieces never appeared.

Anyway, that's just to say that there was justification once for
putting library content in Browse.  Don't know if that justification
still applies.
  --scott

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Re: 10.1.1 and os300 -- DPI vs fontsizes on FF vs Browse.xo

[C. Scott Ananian]

On Tue, Jul 13, 2010 at 1:47 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
 I was aware that maybe we had different in scaling/dpi on our
 browsers, but Aliosh (from the Perú team) pointed out how large the
 difference is between Firefox and Browse.xo:

 Here shown between an XO-1.5 on 10.1.1 and an XO-1 on os300, both
 showing wiki.laptop.org:
 http://dev.laptop.org/~martin/IMG_20100713_133515.jpg

 Browse shows smaller type than on 802 builds (where we were patching
 xulrunner to hardcode 133 dpi...). FF shows things _huge_.

  - Are we doing anything explicit with DPI on the Sugar side? (AFAIK,
 we dropped the xulrunner patch... grepping Browse.xo itself shows
 nothing of interest... )

  - Are we doing anything with DPI on the Gnome side? Why is FF
 super-sizing my internets?

You should probably include the preferences from:
  http://dev.laptop.org/git/activities/firefox-activity/tree/vendor.js
  --scott

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Re: [IAEP] Announce: OLPC software strategy.

[C. Scott Ananian]

It may be worth looking at http://trac.edgewall.org/roadmap for how
the trac team itself uses it.
In particular, if you check the Show completed milestones box, and
then on some old milestone (like, say,
http://trac.edgewall.org/milestone/0.11.3 ) you can drill down into
any component and see what bug fixes it contained.

FWIW, at litl we use two fixed milestones for Future (stuff we're
likely to do in the next release or two) and Far Future (stuff we'd
really like to do, but admit isn't going to happen any time soon).  At
the beginning of each release cycle, we mine the Future and Far Future
milestones for stuff we expect to include in our next release, and
then close/move those bugs as the release approaches.  (We don't use
trac, but the methodology is similar.)
   --scott

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Re: [Sugar-devel] Announce: OLPC software strategy.

[C. Scott Ananian]

On Thu, Jul 8, 2010 at 3:49 PM, Chris Ball c...@laptop.org wrote:
    What about the compiler? IIUC currently a commercial compiler is
    required. If that continues to be the case (as I expect it to),
    would it be possible for OLPC to provide the (probably very few)
    users interested in hacking on the EC code access to a machine
    having this compiler installed? I.e. does the license OLPC has
    for this compiler allow more than one user (on the same machine)
    to use it (if necessary sequentially, ensured by using a lock
    file) and would OLPC be willing to give users access to such a
    machine?

 Good news here too:  we've moved to the free SDCC compiler, so there
 should be no problem here.  I don't know full details, but there have
 been some incompatibilities seen between SDCC and the EC code in the
 past, so staying with SDCC is going to be conditional on being able
 to find a way around those.  SDCC is the plan, though.

 For more questions, I think we should move to the OLPC devel list,
 and I'll let Richard Smith answer because this is his project.  :)

If I understand correctly, the biggest problem is that SDCC lets you
reserve a variable at a specific address, but that *doesn't* prevent
it from using that address for its own automatically-allocated
variables.  This is probably just a linker issue, to detect the
overlapping address assignments -- although if you wanted the compiler
to allocate with holes, that's a compiler issue.

The SDCC source code is very hackable.  This might be something a
volunteer could address at the compiler level.  The alternative is to
very very very carefully read through the legacy EC code to try to
ferret out (and somehow correct) any such conflicts.
  --scott

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Re: NetworkManager time sync

[C. Scott Ananian]

On Wed, Jul 7, 2010 at 12:20 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
 On Mon, Jul 5, 2010 at 11:52 PM, Daniel Drake d...@laptop.org wrote:
 While we have your attention on this topic...
 Do you not think that this is a security issue? In that a thief could
 put a laptop on a network with rigged DNS and have control over the
 time/date on the laptop?

 We *really* have to get OFW clock checks working -- then this
 disappears as an issue. I really want to be able to use ntp (at least
 ntpdate on NM successful connect). The OATS clock sync is very rough
 -- on purpose.

I believe my proposal was to use OFW protected execution to replace
trust the RTC clock -- which is pretty daft, even if theoretically
vserver would let you isolate that priviledge domain -- with having
OFW keep a monotonically increasing counter of CPU time (not real
time).  Theft-deterrence leases would be then good for a certain
amount of CPU time, and you can screw with your RTC all you like.
(CPU time is also guaranteed to increase by some amount on every
boot, so the lease also roughly limits number of boots.)

I think wad said he managed to squeeze the hardware to enable this
into the latest generation, but I don't know if the support was ever
fully integrated.  It's mostly a OFW/EC hack, since all the privileged
code is removed from the OS in this case.
  --scott

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Removing RTC from Theft-Deterrence

[C. Scott Ananian]

Since RTC security is being discussed again, I'm going to repost two
relevant proposals from the good old days.  First: on making
theft-deterrence a feature; then technical details of a $0.16 change
to remove RTC dependence from the theft-deterrence feature.
Unfortunately, the specific circuit changes required are XO-1
specific; presumably some slightly different version is needed for XO
1.5, XO 1.75, etc.  I vaguely remember wad saying he managed to make
this change in hardware at some point; I don't know if corresponding
software was ever written.

Note that the principle here is that OFW and the EC are the only
protected code in the system, and the only pieces which must be
protected from unauthorized update/modification. The EC is a separate
processor running its program independent of OS interference, and so
is the perfect place on which to stand to implement a security
system.  Computation capabilities in the EC are limited, so any lease
validation, cryptography, etc, is done in OFW on the main processor in
the protected run time before the OS boots.  Once the OS boots we
don't expect any additional trusted computation to be done on the main
processor.
   --scott

-- Forwarded message --
From: C. Scott Ananian csc...@laptop.org
Date: Fri, Oct 17, 2008 at 3:11 PM
Subject: 9.1 Proposal: Improving antitheft
To: Devel List de...@laptop.org, sugar su...@lists.laptop.org

I'd like our antitheft support to be more of a feature which G1G1
users could elect to enable, if they like.  This involved making it
much more visible and configurable, most likely putting it in the
control panel.  The idea is if you are taking a trip or leaving home
for a few days, you could turn on theft-deterrence before you go,
get some added tracking/remote-kill features, and then turn it off
later when you get home.

Other topics:
   *  ECO fix and EC improvements
   * Security control panel, with am I stolen and lease renewal
buttons: ticket #1502, ticket #6428
   * olpcrd work: ticket #7397
   * Revoke root capabilities when booted with security enabled: ticket #7562
 --scott

-- Forwarded message --
From: C. Scott Ananian csc...@laptop.org
Date: Tue, Jul 15, 2008 at 1:40 PM
Subject: Re: EC EEPROM security mod.
To: John Watlington w...@laptop.org, Richard Smith
rich...@laptop.org, techteam

Context for tech team: working on a minimal hardware fix that would
provide enough protected real-time clock functionality that we could
enable root and still believe in passive kill for theft-deterrence.

Proposed hardware ECO:
 a) depopulate D31
 b) add Microchip 24LC00T/OT (SOT-23 package), wiring:
     pin 1 (SCL) to SPIWP# (EC GPIOEC)
     pin 2 (Vss) to ground
     pin 3 (SDA) to EC_WP# (EC GPIOE0)
     pin 4 is n/c
     pin 5 (Vcc) to 3VPCU

The 24LC00 part is less than $0.16 in quantity (maybe less from a
Chinese source, there are lots of equivalent parts), some tiny
fraction of which would be recouped by eliminating D31.

This gives us 128 bits of nonvolatile storage accessible only via the
EC.  We use this to backstop the RTC to prevent clock replay attacks
as follows:
 * At boot time, OFW asks the EC to read the EEPROM and takes max(RTC
time, EC time) as its notion of current time when evaluating the
validity of leases. [2010 edit: may want to completely ignore RTC instead, so
that lease isn't shortened by accidentally setting RTC ahead too far
in the future.]
 * At the point where OFW disables writes to the SPI flash, it also
asks the EC to write the calculated current time back to its own
EEPROM.  Writes to the EEPROM after this point are disabled.
 * About once an hour (although it can be as frequently as every six
minutes and still stay within the rated erase cycles of the EEPROM)
the EC increments the EEPROM's value of time with its own notion of
how much time has passed.  We will probably deliberately calibrate
this to be just shy of real time so the EC clock never runs faster
than real time.  (Details below.)

The EEPROM is not accessible except via the EC, and no kernel commands
can cause the EC to either avoid updating or misupdate its internal
EEPROM.  This allows us to give root priviledges to code running on
the main processor without affecting the security of the passive kill
system, addressing the major weakness in the current system.  Lease
times are more properly thought of in terms of powered up time, not
real time, but they still perform their intended purpose.

In my copious free time, I'll try to perform this ECO on a spare
machine and hack up some EC code to drive it to prove the concept.
 --scott

Details for the strong-hearted:
 * Updating exactly every hour is vulnerable to an attacker who
arranges to remove the battery from the machine exactly 55 minutes
after power on, every time.  This is still quite awkward, but to avoid
even this attack, the EC can pseudo-randomly decide exactly when to
update the EC based on a random seed passed in from OFW from the
Geode's HWRNG

Re: [Sugar-devel] Clocks on XOs

[C. Scott Ananian]

On Sat, Jul 3, 2010 at 9:54 AM, Bernie Innocenti ber...@codewiz.org wrote:
 NetworkManager used to call ntpdate when it setup a connection.  Was that an
 OLPC addition?

Yes, although it's now present in litl's software builds as well.

 We figured out that the ntp package has never been present on the XO
 images.

It was ntpdate, which was smaller than the whole ntp package.

 There's no way to practical way to implement effective anti-theft
 without taking away root from the user. And once we take away root
 access, we've also taken away olpc's principle #1: child ownership.

See my recent message on this topic.

Apart from the hardware fix (which avoids RTC dependency altogether),
it is also possible to separate most of root's authority from the RTC
priviledge.  Installing software, for example, requires root access to
the filesystem, but not access to the RTC.

 What are the school servers doing to keep their clocks reasonable?

 They're using ntp, with the Fedora pool of ntp servers.

You should probably apply for your own pool:
  http://www.pool.ntp.org/en/vendors.html#open-source

It's pretty painless, and makes you a better netizen.

  Why aren't we using ntp?

 ntp is probably overkill for XOs.  Besides, who would want to give up that
 much ram?  On top of that, ntpd doesn't get along with power saving mode.

That's why you use ntpdate.
  --scott

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Re: Removing RTC from Theft-Deterrence

[C. Scott Ananian]

On Wed, Jul 7, 2010 at 4:48 PM, John Watlington w...@laptop.org wrote:
 On Jul 7, 2010, at 4:01 PM, C. Scott Ananian wrote:

 Since RTC security is being discussed again, I'm going to repost two
 relevant proposals from the good old days.  First: on making
 theft-deterrence a feature; then technical details of a $0.16 change
 to remove RTC dependence from the theft-deterrence feature.
 Unfortunately, the specific circuit changes required are XO-1
 specific; presumably some slightly different version is needed for XO
 1.5, XO 1.75, etc.  I vaguely remember wad saying he managed to make
 this change in hardware at some point; I don't know if corresponding
 software was ever written.

 The EEPROM needed for this was included in early XO-1.5 prototypes,
 but was dropped from production due to the lack of software making use
 of it.   It could be added back to any XO-1.5 SKU for a slight cost increase.

Unfortunately, the software changes required are to EC code, which is
difficult for outside contributors to work on.  (Also some OFW work,
but that's available and easily hackable.)
  --scott

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Re: [Sugar-devel] Activity packaging

[C. Scott Ananian]

On Wed, Jul 7, 2010 at 2:16 AM, Aleksey Lim alsr...@member.fsf.org wrote:
 On Wed, Jul 07, 2010 at 01:18:04AM -0400, Michael Stone wrote:
 Bernie wrote:
 On Tue, 2010-07-06 at 12:02 -0400, Benjamin M. Schwartz wrote:
  I think you are missing an important requirement: installation without
  elevated permissions.
 
  Rainbow has been bit-rotting for the past 2 years

 Ahem. Sugar's integration with rainbow has bit-rotted, been rebuilt, and 
 still
 received no independent testing despite repeated calls for same.

 Rainbow, on the other hand, has seen a major new release, feature development
 that spurred new work in general Linux sandboxing, and is now available in 
 more
 distributions than ever before thanks to dedicated support by folks like 
 Luke,
 Sascha, and Jonas.

 Finally, if rainbow itself now receives little day-to-day attention, this is
 because it mostly does what its authors require and it does it well enough 
 not
 to require their continued hand-holding.

 To be honest I wasn't a fan of rainbow a bit time ago..
 But having Zero Sugar fully implemented and potential possibility to launch
 almost any piece of software  - compile on demand is a regular workflow within
 0install (existed sugar doesn't not let such possibility:), rainbow should
 be more then essential requirement.

I took some time to read up on 0install -- very impressive technology,
good work.   I agree with Michael that this (userland installs) is the
direction Sugar should be pursuing.  With rainbow (or other sandbox)
integration, this would accomplish all of the original goals with a
much more robust packaging and dependency system than the .xo bundle.
  --scott

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Re: Removing RTC from Theft-Deterrence

[C. Scott Ananian]

On Wed, Jul 7, 2010 at 4:01 PM, C. Scott Ananian csc...@laptop.org wrote:
  * Updating exactly every hour is vulnerable to an attacker who
 arranges to remove the battery from the machine exactly 55 minutes
 after power on, every time.  This is still quite awkward, but to avoid
 even this attack, the EC can pseudo-randomly decide exactly when to
 update the EC based on a random seed passed in from OFW from the
 Geode's HWRNG, with an *average* interval of an hour.  We probably
 don't have to perform this extra trickery if we just shorten the
 interval to 6 minutes or so, but the means that the EC's EEPROM will
 wear out at the end of the 5 year service life of the machine.  We can
 probably detect this condition (EEPROM no longer writes reliably) and
 just disable passive kill security at this point, though, which might
 be nice for freedom-loving reasons.

2010 thoughts: I like the idea of pseudo-random updates.  Having a
uniform 1/60 probability of update every minute makes powering off as
a circumvention mechanism pointless, while reducing EEPROM writes.  A
very simple linear feedback shift register for generating
pseudo-random bits would be sufficient, since the inputs and outputs
of the system are hidden.
  --scott

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Re: USB2VGA adapters on XO-1.5 (and XO-1 with F11 images)

[C. Scott Ananian]

On Fri, Jul 2, 2010 at 4:53 PM, Martin Langhoff
martin.langh...@gmail.com wrote:
  - It is slow and laggy. A VNC protocol expert may be able to help us
 optimise...

Might try some of the VNC encoding options, like those at:
 http://www.realvnc.com/products/free/4.1/winvncviewer.html#ColorEncoding
Assuming you're using a Unix domain or localhost socket, the raw
encoding might be best, with # colors matched to the source/dest.

  - If you look carefully, the mirror session has a small square cursor
 in the middle of the screen. We need a variant on
 http://wiki.x.org/wiki/AdvancedTopicsFAQ#Iwanttomakethemousecursorinvisible
 but I could not make it work. Given how the technique works, I think
 vncviewer is overriding the root window cursor.

This is a feature of vnc -- since the remote system cursor may lag
your local cursor, VNC represents your local cursor with a small box,
so that any mismatch between local and remote cursors is obvious and
visible.  The UseLocalCursor option to VNC should affect this.  (You
also might want to look into AutoReconnect.)

I'm using the names of the options in the official vnc viewer, but I
think the open source ones have the same options, maybe spelled
somewhat differently.
  --scott

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Re: Removing RTC from Theft-Deterrence

[C. Scott Ananian]

On Wed, Jul 7, 2010 at 6:54 PM, John Watlington w...@laptop.org wrote:

 On Jul 7, 2010, at 5:07 PM, James Cameron wrote:

 On Wed, Jul 07, 2010 at 04:57:19PM -0400, C. Scott Ananian wrote:
 Unfortunately, the software changes required are to EC code, which is
 difficult for outside contributors to work on.

 Yeah, that would be good to change.

 Have you forgotten that Richard and I have been working
 to get that changed for XO-1.75 ?   Or did we forget to report it ?

I hope that XO-1.75 will also have space for a small serial flash on
the motherboard then. =)
  --scott

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Re: NetworkManager time sync

[C. Scott Ananian]

On Mon, Jul 5, 2010 at 9:03 AM, Bernie Innocenti ber...@codewiz.org wrote:
 On Mon, 2010-07-05 at 10:33 +0200, Tomeu Vizoso wrote:
 You mean a script placed in /etc/NetworkManager/dispatcher.d/ ?

 Yes, and then invoke hwclock --systohc.

 I was just hoping to find something already written, tested and packaged
 nicely so we could use it both on the XO and SoaS.

I wrote that script when I was at OLPC.  It should still be packaged somewhere.
 --scott

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Re: NetworkManager time sync

[C. Scott Ananian]

On Mon, Jul 5, 2010 at 8:33 PM, Bernie Innocenti ber...@codewiz.org wrote:
 On Mon, 2010-07-05 at 20:30 -0400, C. Scott Ananian wrote:

 I wrote that script when I was at OLPC.  It should still be packaged 
 somewhere.

 I see olpc-update-ifup in my builds, but nothing related to ntpdate.

 Do you remember if it was part of olpc-utils or olpc-update?

Maybe someone's got a copy of build 653 lying around and they can run
rpm -q for us.
  --scott

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Re: NetworkManager time sync

[C. Scott Ananian]

On Mon, Jul 5, 2010 at 11:52 PM, Daniel Drake d...@laptop.org wrote:
 On 5 July 2010 21:44, C. Scott Ananian csc...@laptop.org wrote:
 Maybe someone's got a copy of build 653 lying around and they can run
 rpm -q for us.

 While we have your attention on this topic...
 Do you not think that this is a security issue? In that a thief could
 put a laptop on a network with rigged DNS and have control over the
 time/date on the laptop?

A sane security system would let the user control their local time,
without jeopardizing security based on server (or firmware) time.
  --scott

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Re: New keyboard layouts

[C. Scott Ananian]

On Wed, Apr 28, 2010 at 5:19 PM, James Cameron qu...@laptop.org wrote:
 Australian teachers that I've met have pointed out that their kids are
 primarily taught lowercase letters, and would prefer a keyboard to be
 marked with lowercase letters rather than uppercase letters.

 Not having looked at the key legends for about 28 years, I was
 surprised.  ;-)  What a fascinating idea.

+1.

The litl webbook's keyboard, FWIW, is labelled with lowercase letters.
 I always thought that was something that OLPC didn't quite get right.
 Young kids are surprised when the letter they press doesn't match
what shows up on the screen.  Lowercase looks nice and friendly, too.

OTOH, this keyboard is meant for older students, so maybe it's not as
big a deal.
  --scott

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Re: multi-touch

[C. Scott Ananian]

On Tue, Jun 8, 2010 at 4:20 AM, Carlos Nazareno object...@gmail.com wrote:
 If possible, go for a minimum of 5 touch points capability, which is
 what Apple has I think.

Apple actually supports 11 on the iPad.  Palm and the iPhone support 5.
   http://daringfireball.net/linked/2010/05/10/gemmell-multitouch
  --scott

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Re: Touchscreen requirements

[C. Scott Ananian]

On Tue, Jun 8, 2010 at 9:23 AM, John Watlington w...@laptop.org wrote:
 An interesting effect I've noticed is that with some touchscreen, you get 
 smooth
 lines when moving your finger at a normal speed, say 8 cm/s, but when you 
 slow
 down (1 cm/s) the line wiggles around.

See http://labs.moto.com/robot_touchscreen_analysis/

Strength of touch also matters a great deal, and there's quite a bit
of fudging being done in the hardware tracking algorithms.
  --scott

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Re: Touchscreen requirements

[C. Scott Ananian]

On Tue, Jun 8, 2010 at 11:14 PM, John Watlington w...@laptop.org wrote:

 The mini cocktail wieners I'm familiar with are still
 around 8-10mm.   I guess I could carve one down
 and wrap it in plastic...

Gummy fingers are more fun: http://cryptome.info/0001/gummy/gummy.htm
 --scott

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