NodeJS + CouchDB Concept in Action

Here is the concept in action:
http://siddiq.no.de/dubai-gold-rates.html

This app is pure Javascript:
A complete Javascript stack is not only a reality, its fun.


1. Backend Server Language
Javascript running in NodeJS (http://nodejs.org) hosting on Joyent for free. See http://no.de

2. Database stored procedures Language
Javascript running in CouchDB (http://couchdb.apache.org/) hosting on IrisCouch for free. See http://www.iriscouch.com/service

3. Front-end GUI + Charts (No flash used i.e. HTML5 + CSS3)
HighCharts uses HTML5 + CSS3, so you don't have to use Flash. http://www.highcharts.com/

SOLVED /etc /sysconfig /modules /VirtualBox-OSE.modules

I updated kernel and my VirtualBox-OSE stopped working. Asking me to run this command: /etc/sysconfig/modules/VirtualBox-OSE.modules

But this command would fail with following error.
$ sudo /etc/sysconfig/modules/VirtualBox-OSE.modules
ERROR: modinfo: could not find module vboxdrv
ERROR: modinfo: could not find module vboxnetflt
ERROR: modinfo: could not find module vboxnetadp

SOLUTION:
The easiet solution is to download stable package from the site, instead of resorting on yum repos:
http://www.virtualbox.org/wiki/Linux_Downloads 

NOTE :
This happens becuase yum repos are not updated soon after the kernel is released. It usually takes hours and days depending on the packages.

Awesome NodeJS performance on a VM in Joyent cloud

VM running on Joyent cloud has a very fast processor.

Having some fun, crunching a number on my machine vs a smart machine on joyent cloud.

Here is the code:

sys = require('sys');

var counter, d, d2;

// sync with clock
d = new Date();
do {
    d2 = new Date();
} while (d.getSeconds() === d2.getSeconds());

// run for a second
counter = 0;
d = new Date();
do {
    d2 = new Date();
    counter ++;
} while (d.getSeconds() === d2.getSeconds());

// the number that was crunched
sys.puts('counter = ' + counter);

My machine specs:
Intel core2 duo 1.6GHz * 2
2GB RAM

Joyent SmartMachine:
Vistual machine with some SPARC server machine as host
128MB RAM

gitk looks ugly: qgit vs gitg vs gitk

A quick comparison between gitk vs gitg vs qgit and why gitk looks ugly?

	gitk	gitg	qgit
Version	1.5.6.5-3	0.0.6	2.3
GUI	Tcl/Tk	GTK	Qt
Looks	ugly	awesome	less awesome
Speed	fast as expected	very slow	very slow
Features:	search only	basic search only	more features then gitk and gitg

Acquiring packages:

• sudo apt-get install gitk
• sudo apt-get install gitg
• sudo apt-get install qgit

gitk:

• Nice visualization but a scary gui. Look at the buttons you cant tell they are pressed or unpressed. The gui problem is also because its based on tk/tcl which doesn't honor the GTK theme.

• After showing the initial view, it keeps running a background process to scan local uncommitted changes which are finished in 45 seconds for my project. Which is a cool feature.

gitg:

• Provide the awesomeness of gui that is expected in gnome. i.e. proper GTK theme settings.  

• The problem is that its slow. It says "Loaded 1893 revisions in 32 seconds.". Even if I turn off the options to show stash/staged/unstaged changes I still wait for 32 seconds to load the history on my project.

qgit:

• Loads 1893 revisions and directory changes in 61 seconds. But if you turn off 'check working directory changes' then it becomes very fast and loads in less then 5 seconds.

• Provides more features then gitk and gitg.

• A little less awesome then gitg bot a lot more awesome then gitk.

Recursively delete .svn directories in Linux

See the .svn folders:

$ find . -type d -name .svn
./.svn
./js/.svn
./tests/.svn
./tests/js/.svn
./assets/.svn

Delete the .svn folders (pass the output to rm -rf):

$ rm -rf `find . -type d -name .svn`

You may want to create a shell script to automate...

Facebook Credits Integration for Developers

Just like many other developers I was interested in Facebook Credits testing program. Still waiting for their beta launch.

For signup for beta testing program you may want to sign in here:
http://facebookcredits.questionpro.com/

Other options for virtual currencies

• Direct credit card transactions
• PayPal
• Google CheckOut
• Amazon Payments
• Mobile payments (Zong, PayMo, Mobill Cash, etc)
• Affiliate providers (SuperRewards, OfferPal)
• Third party virtual currencies (e.g., SpareChange, Social Gold)

Facebook Credits Pros and Cons
As not much specifications annouced from facebook so we can only speculate with limited details and what industry specialists say about it.
Pros
- Simple interface for customers. Less clicks.
- More trust
Cons
- Platform not much tested
- Can't completely replace other Virtual Currency providers. So developers have to maintain parallel systems.

Some Apps that are currently using Facebook credits:

• Zoo World — Zoo World
  
• Crowdstar — Happy Aquarium (7.3 million DAU), Happy Pets (2.9 million DAU), Happy Island (just launched)
• Playfish — Restaurant City (4.2 million DAU)
• HitGrab — MouseHunt (173,000 DAU)
• Zynga — Pirates: Rule the Caribbean! (159,200 DAU)
• Playdom – (Lil) Green Patch (79,228 DAU) and TikiFarm (just launched)
• GPI – Robin Hood (11,104 DAU)
• Alamofire – PackRat (8,442 DAU) – although I couldn’t identify the integration point

I was surprised to see FarmVille not in the list.

Code Jam 2009 and the glory of China continues

The winner is Lou TianCheng from China followed by Qi ZiChao (China) and Iwata Yoichi (Japan) respectively.

See the difference, such a big leap the winner had.


Here is the list of finalists with ranking.

Position	Country	Participant	Score	Penalty
1	China	ACRush	168	03:10:13
2	China	qizichao	87	03:59:29
3	Japan	wata	81	03:42:15
4	Russia	ZhukovDmitry	70	04:07:59
5	Ukraine	dzhulgakov	69	03:23:57
6	Georgia	nika	62	02:36:34
7	Russia	Vitaliy	62	04:06:31
8	Croatia	kalinov	55	03:57:38
9	Russia	halyavin	54	03:55:29
10	South Africa	bmerry	50	03:30:12
11	Ukraine	Slyusarenko	50	03:32:13
12	Poland	marek.cygan	45	03:29:21
13	Vietnam	Khuc.Anh.Tuan	45	03:59:27
14	Taiwan	Jiunru	35	01:44:16
15	Russia	winger	32	02:51:28
16	Japan	hos.lyric	30	03:50:08
17	Russia	pashka	30	03:57:18
18	Slovakia	misof	30	04:11:40
19	China	Jeru	23	03:28:29
20	Lithuania	FloppyCat	18	04:02:16
21	Germany	AdrianKuegel	15	02:55:00
22	Russia	emaxx	13	02:31:57
23	United States	ploh	3	03:57:28

One of the interesting fact is that the most popular language was C++ followed by Java, C and Python.

For more on Statistics by Language and by Country:
http://go-hero.net/jam/

Official Page
http://code.google.com/codejam/