pavelmachek's Journal

10:11am: ntp vs. hibernation
My work machine has ntpd running; still times go off; last time I checked it was off by 11 seconds.

Looks like ntp is one application where "hey, we have just woken up from sleep" notification could be useful... or perhaps ntp should just monitor how much time passed between invocations, and do full resync at that point?

11:09pm: Androids doing endurance racing
So we won endurance race for 22km in Borotin with my little pony^Wfjord. And now I've seen the results... and we should have been 9th. For some reasons, in 'hobby ZM' they time you between finish and veterinary check. You have minimum speed set, but still...

Timing between start and finish encourages you to push the horse to the limit (which I did, anyway, but...), so I understand that is not suitable at the lowest level. I'd understand timing between start and veterinary check... but what is rationale for timing finish to vet check only?

Anyway, there's now app for that. Endurance riding app. Beware that GPS and wheel-based trail measurement often differ by 10% or so...

10:36pm: New 16GB sdhc card...
...and of course it does not work too well. PC fails to recognize it sometimes, HTC Dream consistently will not recognize it when present during boot. I guess it goes back to ALZA, but I'm not looking forward to dealing with them...

mmc0: card claims to support voltages below the defined range. These will be ignored.
mmc0: SD card claims to support the incompletely defined 'low voltage range'. This will be ignored.
mmc0: error -84 whilst initialising SD card

AData microSDHC, 16GB. When it works, it is

mmc0: new SDHC card at address b368
mmcblk0: mmc0:b368 SD    15.4 GiB 
 mmcblk0: p1 p2 p4

9:37pm: yookos: what kind of scam is this?
I'm periodically spammed by "[Yookos] Announcement"s. Yookos apparently thinks my email address corresponds to Peter Hedlund. What kind of scam is this?

6:08pm: OpenMoko dead battery tip
Quite often, if you leave battery in OpenMoko for too long, it goes totally dead -- OV on terminals, internal protection kicked in, impossible to charge in OpenMoko. But put it into nokia 6230 (yes, it fits)
connect charger. Voila, battery that had 0V on its terminals now has something over 3V, and can be (very slowly) charged in OpenMoko.

2:35pm: Open Source light
HexBright. Yep, it is open source, but it was definitely not the first one. Ok, maybe my tinylight never got such a nice case, and only one was ever made, but...

9:44pm: How do you deal with good camera
So I got myself Sony Alpha A200 DSLR. Before, I was able to take 100 2-megapixel photos with historical Kodak toy, deleted half of them, hand-selected 5 really nice photos, and everything was fine.

Today, I took 920 photos, 2.5GB total (and that is far from max resolution). How the hell I'm supposed to sort that?

Oh, and my sister got driving lesson after not driving for few years. Pala (== Skoda Forman), which implies difficulty = high. Original motivation was empty battery... Which was bad news #1: you may not let the engine die, because we'll not be able to restart it. Bad news #2 was relatively innocent: parking brake does not stick in the "parked" position. And then came bad news #3: engine temperature reached the red line, so electrical cooling is probably broken and you may not go too slow.

Congratulation to my sister, because she was able to drive for 30 minutes without incident, and without engine dying. She should be able to drive any kind of trash with four wheels from now on.

(And she probably believes me that car is way safer than a horse).

12:31pm: windowmaker with dualhead
So... doing xrandr to add second monitor is easy and works well. But... moving windows to the second monitor is not easy, if you are using windowmaker -- as soon as the mouse crosses the monitor boundary, it switches to next virtual desktop. Ouch. Is there handy setting somewhere? Or should I just switch to some more modern window manager?

3:54pm: Java, Androids and ALSA
So this is why I hate java: MediaPlaybackService.java. See especially the "reverse hexadecimal" part. Half of the code is trivial functions hiding internal variables, and the other half is working around the fact that Java is just too slow...

Single process eating 100% cpu seems to be enough to make Dream unusable. (Is that normal?) I guess I should use nice extensively... But I wonder why it is so sensitive, Linux scheduler is normally clever enough to deprioritize those.

Oh and tip of the day: if ALSA mysteriously stopped working for you (but /dev/dsp emulation still works ok), you may want to disable "SND_DYNAMIC_MINORS" option... or maybe finally install udev.

10:39pm: Android notes
It was bad idea to change the hostname. sl4a mysteriously stopped working. sl4a is now single most important application on my android, because I use it to launch ... shells into debian chroot. So now I'm stuck looking at "localhost".

Warning when application is unresponsive seems like good idea -- it forces developers to make their apps responsive. But... then you load the system up. For example by offlineimap mail sync. And you get the
warnings from random applications ("Process com.google.process.gapps is not responding", wait/force exit) quickly followed by bug reporting process itself being reported as unresponsive. Ouch. Is there easy way to disable this or at least increase timeouts?

(And yes, this means I turned G1 into yet another Unix machine.)

11:15pm: power matters
So... just because something needs 5V does not mean you should charge it from USB.

Yes, I'm talking about zaurus. I noticed that it crashed rather quickly when connected to USB power. (For example in tar/rm test, dies in less than five minutes). So I took multimeter, and there was 4.15..4.5V on USB :-(. With _good_ 5V source, connected by thick cable, zaurus is stable for hours.

I guess it is software problem in the charging code, but...

10:58pm: Drive-by-wire
Ok, so I had "small" problem with a car. Stuck brake on front right wheel produced a lot of heat.

After repair, front left wheel produces heat. Ouch.

But.. those are only brakes, and Forman has two independent vehicle brakes, handbrake and you can use engine to slow down. That's four more brakes then my horse. I guess I should feel safe?

But for some reason drive-by-wire systems in cars scare me. I guess I just don't trust the software, and I do not trust computers in cars. That's the good thing about Skoda Forman -- only electronics seems to be the radio receiver. If that car had electronic, it would refuse to move long time ago. I had to start it by letting it go downhill, first... That would be a big no-no for drive-by-wire system... unfortunately such cars are rare these days.

I wonder when "no electronics in safety-critical system" cars will be rare?

10:44pm: Android 2.2 on G1 (HTC Dream)
Ok, Cyanogen offers that, and it is quite nice and very quick... as long as you don't launch any applications.

Using just one or two applications is okay, but when you launch more than that, it starts to be really horribly slow. As in "I'm now waiting two minutes for characters to echo in local shell". Unusable.

Should the OOM killer trigger and kill unused applications at this point? Or is just Android 2.2 too big for old device like HTC Dream, and I should go back to Android 1.5?

(I have an application that needs Android 1.6+ unfortunately, and IIRC Android 1.6 was even worse than Android 2.2 on Dream -- it was not even quick after startup.)

10:05pm: Python on android
...aka usable scripting for your phone. Android scripting can do a lot, and is reasonably easy to use. Unfortunately, not everything works properly on my historic HTC Dream (notably reading battery state), but it is still userful. So far I have a script that turns on wifi where it makes sense, and a lot of crazy ideas.

8:27am: TI Chronos emulator gets SDL interface
Thanks to Cyril Hrubis, who created .svg version of (parts of) TI Chronos display, I forced myself to create a SDL interface to chronos emulator... so you no longer have to run emulator on console and watch the ascii art.

Code is at http://sourceforge.net/projects/mychronos/ .

For now, I just did png export, and then edited each image manually -- to add transparency. I wonder if it would be possible to somehow tag subtrees in svg and then have them automatically exported as right icons..?

7:20pm: bufferbloat
Yes, I do have severe bufferbloat problem:

64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=233 ttl=53 time=15.9 ms
64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=234 ttl=53 time=16.2 ms

64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=235 ttl=53 time=37691 ms
64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=236 ttl=53 time=36835 ms
64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=237 ttl=53 time=35839 ms
64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=238 ttl=53 time=35257 ms
64 bytes from atrey.karlin.mff.cuni.cz (195.113.26.193): icmp_req=239 ttl=53 time=34256 ms

And that's 6Mbit ADSL from O2, with single scp "up". But, used to GPRS speeds, I just assumed that's the way life is... and used rsync --bwlimit as a workaround. Oops.

7:19pm: Prague public transport system: treating people like dogs

So... to travel with Prague public transport, you have to get remotely readable chip, like it or not. You can either give them all the personal details (including stuff completely irelevant to transport) and agree to draconical agreement (where they reserve right to sell your personal data), or pay $10 for a card, and then $10/month extra.

To make it worse, you can only get the "anonymous" card at one place in Prague, and today I learned that it seems to have "expiry date".

So actually dogs are treated better than Czech people, they don't have to travel halfway across the city to get their chips, don't have to wait in queue to get them, and they don't expire.

8:08pm: DSLR is a nice toy
...but it produces *huge* pictures (like 12MB each) in RAW+JPEG mode. I'm using CF to PCMCIA... and well, that sucks. Interrupt latency (or what is that?) is so high that keystrokes are lost in X (and I'm using PS/2 keyboard). Sometimes key _release_ is lost and.. that's bad.

Is there really no way to use PCMCIA without making system completely unusable? (Hmm, can I just enable DMA on CF disk?). Machine is unusable for 30 minutes now...

11:11pm: DSLR to play with
I made myself an early christmas, and got (used) Sony A200 + 18-70mm + 70-180(300)mm objectives. That beast is able to shoot images in the dark... So far it looks good. Inpoor lighting, it is a tiny bit slow, and *smallest* image it can produce is 1.6MB so processing takes time, but... it is huge step ahead from Olympus C-765 and old Kodak DX3600...

8:53pm: TP-LINK TD-8810B ADSL router (aka the cheapest one I could find)
I was surprised when I opened the box, and first paper was GPL. I was surprised even more when I telneted to the machine, typed "sh" and got busybox as root.

The reset of the day was not that nice -- I called O2, they closed the deal, and only after that told me that it will take up to 7 days to mail me the ADSL passwords -- using snail mail. Ouch.

Ok, fortunately they sent me SMS after 4 days, and I was able to call them and get the config. Good so far.

9:57pm: rsync assisted by usb stick
So I use rsync to transfer big files over slow network, use USB stick to (by hand) speed up the process - by transfering big files I knew are changed to the USB stick and then to the other system, relying on rsync to set up correct attributes etc.

And now I wonder... surely someone has scripts/special utility to do this automatically?

8:53pm: Daylight saving time sucks....
But at least it is chance to re-adjust all the clock. Unfortunately, every little device now has clock... so that's quite a lot of work. But at least time will be right... for a while.

Time from digital TV... 3 seconds off. I thought modern electronics could do better.

Plus it looks like O2 finally learned to limit data transfers on UMTS, so I'll need new connection, probably ADSL. Is there good place to get used ADSL modem?

8:55pm: android: 2 batteries a year
It seems HTC Dream (aka T-mobile G1) eats two bateries a year. You say "Not bad, having to recharge once in six months"? Unfortunately, thay's not what I meant. It discharges two accumulators per day, and it physically destroys two accumulators a year :-(.

That seems like a bit much... (do other users have similar experience?) Perhaps it is my heavy usage of tethering while charging? Or is it car charger? Or strange charger from single AA I used long time ago?

HTC Dream has USB connector for charging. Does it mean it should tolerate anything from 0V to 5.5V?

What is worse, the batteries are hard to get in Prague. For a phone that needs so many of them, that's quite surprising.

11:52pm: plush velvet terorist


So I have a rather yellow (red-dun fjord) and rather free (you can't force him to do anything, but he'll do almost anything voluntarily) horse, with a bad name. "Ruppert" sounds too close to certain nasty word in czech.

This weekend he got another nickname "plysovy terorista" (plush velvet terorist). He certainly looks like toy made from plush velvet ... that is, unless I work with him ... and every litle girl falls in love with him.

Well, and the second part... we put him in quite a big paddock with significantly bigger arabian horse that did not know him. Of course I was woried that arabian would hurt my pony.

And as you can guess, my pony was unscratched next morning. (To be fair, the other horse was only scratched a bit).

Unfortunately, neither "free horse" nor "plush velvet terorist" nor "yellow horse" are suitable names. Any ideas how to call him?

11:46pm: how to pair bluetooth devices in 2010
Apparently, bluetooth subsystem changes in incompatible ways every
year or so. So, in 2010, you need to:

start bluetoothd (hcid no longer exists)

hciconfig hci0 piscan

run bluetooth-agent (passkey)

initiate pairing from other device

Setup the other device to allow auto connections.

Pins in config files no longer work. On the other hand, bluetooth-agent is nice to use rom command line, and new command names actually make sense. Perhaps they will last more than a year?