dev/n0ll

One of my good friends has started on a big adventure. Travling around the world with a sailboat. With 3 friends he set sail from Arendal. And where do I come into the picture? Well, I’ve been helping them building a webpage/blog, with some cool features. And that’s what I’m gonna talk about now!

SPOT-Tracker
On board they have a satellite SPOT tracker.Witch gather and send GPS location to a SPOT service. They make the data available through some interfaces, a pre-made widget and raw XML data. The pre build stuff sux! Sorry, but this should be a lot better so that the “man in the street” can actually get something useful out of it. But for the geek, they also provide XML data. Witch you can do a lot of fun with….

Satellite Tracer
First of, I need to build a widget that would display their whereabouts. Since SPOT provides XML data, it shouldn’t be huge issue. Using PHP’s SimpleXML the task was done quite fast. (After learning about PHP and XML….). When I finished I thought, this is quite good, maybe somebody else would like to use this as well. So I sent an email to SPOT, to see if they would like to publish it on their site. Still no answer from them…

Nothing fancy, and can probably be written better, but it’s clean, small and it works:
File: SPOT.phps

Collection historical data
SPOT only save position for a certain time. I think it only save the last 7 days. And that’s no good if you going on a longer trip! So my first though was to just ‘wget‘ the XML file and save it locally. But I quickly found out that this would be a big mess if you wanna use the data on a later stage. Time to write a XML Data Collector!

Using what I’ve learn from when I built the satellite tracker, and googled my way to add children to an existing XML file, I had the idea, and it was time for some coding.

Due to the add_children function in PHP, you can only add to the end, not append to the top. I had to reverse my xml, so that the latest “message” was saved at the bottom.
File: XMLDumper.phps

And when you do all this, you’ve learn PHP and XML handling, I couldn’t just let it be with this. I had to use my newly created XML files for something useful! Using google API, I could created a map that would show their route from the start too their current posision. Check out Blue Water Sailing – Travle Map
If you wanna see how the widget works. Take a look at http://www.bluewatersailing.no/

**Update:
Playing around with xml/php and google MAP API, I’ve now upgraded TravelMap to include “traveled route”, and with a planed route. The planed route is made i Google Maps, and is controlled by the guys how is sailing. It means that they can put what ever they want onto the map, and it’s automatically updated on the website. Long live KML data!
Updated map:

We’re getting closer… it’s now time!

After receiving offer from several contractors, and got an estimated on how much it’s gonna cost,
(witch was within our budget), it’s now a GO for new house in Voss!

And to document the whole building process, I’ve mounted a DSLR camera on the old garage,
witch will be taking pictures, and compile a timelapse movie of it all.

A newly created website has been dedicated to the process: Lekve.org

10 years ago a browser was born.
Its name was Internet Explorer 6. Now that we’re in 2011, in an era of modern web standards, it’s time to say goodbye.This website is dedicated to watching Internet Explorer 6 usage drop to less than 1% worldwide, so more websites can choose to drop support for Internet Explorer 6, saving hours of work for web developers

Support the cause by joining the movement! Let’s get rid of a really old old browser!

Source: http://www.ie6countdown.com/

Lekve

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Sometimes you surf around the internet, and suddenly you find something cool or interesting.
This time I came over something called Time-lapse.

From wiki;
Time-lapse photography is a cinematography technique whereby the frequency at which film frames are captured (the frame rate) is much lower than that which will be used to play the sequence back. When replayed at normal speed, time appears to be moving faster and thus lapsing.

And since we are in the planning stage of building a new house… how cool would it be to timelapse the house building?
Time to get some equipment. Silje had an old Canon 350D, but then we needed to get a new one for her……

Off to see what we could get, ended up with a brand new Canon EOS 555D.
It’s a big difference between the 350D and the 550D, and after some test picture, you can see the difference was huge! And while crawling around on the web, searching for cool things to do with the new camera, I came over something called HDR. I’ve heard about the technique before, but now I had the equipment to do it myself, check out my first HDR pictures above.

There are also some test “time-lapse” movie that will be published shortly.
(and there are even more gadgets incoming….)

Well, it wasn’t suppose to be that easy……

Getting some very mixed results.. it’s was time to get back on the test bench.
Playing around with iperf I knew that OpenVPN tunnel should be able to push enough bandwidth. Guess it was time to play around with the NFS options again…

Since I’m only interested in read speed, this is the only thing I tested.
To make variation in latency for the different test, I used only a 16MB file for testing.

Test command:

mount_nfs -o rsize=$rsize,vers=4.0alpha,ro,async,noatime $HOST://$RM /$LM
dd if=/path/to/testfile of=/dev/null bs=16k
umount /$L_mount
sleep 10

$rsize= rsize for testing (default, 1024,2048,4096,8192)
$HOST = NFS HOST
$RM = Remote NFS Mount Point
$LM = Local NFS Mount Point

Test run on a 30min interval and was doing during the night.

Initial conclusion is that I need to change my `rsize`… Will do some more testing during daytime, to see if variation in latency (usually more variation and bigger during day..) will effect the performance (it should do, but the best rsize will hopefully be the same….

It might be time to change out my low end router, a Linksys WRT54GL, witch is place between the client and internet. As you can see from the graph bellow the load is quite heavy.

I’ve been doing quite some testing earlier that evening, but you can clearly see the spikes in load when the test is do. Check the intervals just after midnight..

***UPDATE ***
Done some more testing, and here are the results

After first test, I could easily scrap 1024 and STD. But it was a close call with high rsize. It was time to check if even high size would matter.

In the second test, I also created a bigger testfile. Since the variation in speed and latency where to big to make a final conclusion.

The third test, I added yet a higher rsize. But as the results shows, I had found the highest already. When using 16384 the read speed slowed down again…..

Conclusion
mount_nfs -o rsize=12288,vers=4.0alpha,ro,async,noatime 192.168.0.1://media /mnt/media/

It’s a close call between 12288 and 8192… Not sure what is best… I’ll start using 12288 as it is slightly better on average…. Maybe I’ll do a intense test on only these to values on a later point….