WSRM allows greater control over the CPU and Memory available to a process and is an additional feature shipped with Windows Server that can be installed from the server manager under “Features Summary”:

Once installed we need to create a new resource allocation policy from the manager:

and give it some name:

Now we need to select processes to match with the policy:

We will select process from the list of registered services:

Here we find MongoDB:

Click OK a few times to exit the process selection. On the memory tab we can limit the memory for this resource allocation policy:

The final step is to make the policy active. To do this, go to the top level page in the manager and click the “Selected Policy” link. In here you can set the active policy:

That’s it! Now MongoDB will not consume more than 500MB of memory.

A problem with the current implementation is that I have not found any way to index histograms, so when searching the input image needs to be compared to each image in the database (O(n) yay!). For larger datasets this would of course not be feasible, but at least the problem is easy to scale over several CPUs, so I can take advantage of all my cores.

You can find ColourSearch on GitHub (code in C#, works perfect under Mono!):
https://github.com/moberg/coloursearch

If you have any ideas on how indexing can be done or on more efficient matching algorithms I would be very interested in hearing them!

http://www.pitorque.de/MisterGoodcat/post/Unlocking-a-Windows-Phone-7-device-for-development.aspx

So together with the SDK a small activation program was installed, “Windows Phone Developer Registration”. Start it and login to active your device!

This blog post has great step by step instructions on how to force the update:
http://nokiagadgets.com/2012/03/08/force-the-newest-lumia-800-update-1600-2487-8107-12070-to-your-phone/

Basically what you have to do is to download the update and install some tools for phone developers. Once you have downloaded everything you run the “WP7 Update Cab Sender.bat”:

The update process takes about 10 minutes. The first thing I tested out after updating was of course to play some music, the audio is indeed much improved. Time will tell if the battery performance got better!

The team I was in consisted of me, Tomek Augustyn, Patrik Spathon and Pebbles Lim. Tother we came up with the idea to build a multiplayer version of the classic game pong, but using motion detection to control the game. We named the game Spong:

Each player runs the game from his web browser, which will access his web cam using WebRTC. The motion detector analyzes the video stream and detects where the most amount of movement is, this gives us a coordinate on the screen. The Y part of this coordinate is used to control the position of the players’ paddle. You can see this in the image above where the cross points out where i just moved my hand. Each players’ movements is sent to the other player via a Node.js/Socket.IO relay server.

To summarize Protothon #2 I must say that I was really impressed with all the applications presented by the different teams. It was one intense day, but a lot of fun! I am looking forward to attending again in the future.

First, we need a configuration file for the nginx site. If you haven’t already got nginx installed, install it (sudo apt-get install nginx).

/etc/nginx/sites-enabled/mvc:

server {
    listen   80;
    server_name mvctest.sourcecodebean.com;
    root  /home/peter/MonoMvcDeploy/;

    location / {
      root /home/peter/MonoMvcDeploy/;
      index index.html index.htm default.aspx Default.aspx;
      fastcgi_index /Home;
      fastcgi_pass 127.0.0.1:8000;
      include /etc/nginx/fastcgi_params;
    }
}

Type “sudo service nginx reload” to reload the configuration. Browsing to the site should give you a fastcgi error since there is no fastcgi server listening on 127.0.0.1:8000 yet. So far this is a good thing and shows that your configuration is correct.

Next we create a start script for our fastcgi server.

/home/peter/startmvc:

#!/bin/bash
source ./monoenv.sh
fastcgi-mono-server4 /applications=/:/home/peter/MonoMvcDeploy/ /socket=tcp:127.0.0.1:8000

This is pretty straigt forward, the only thing that might be a bit confusing is this part “/:/home/peter/MonoMvcDeploy/”. This means that we want to map the URL / to the application in /home/peter/MonoMvcDeploy/. This allows us to run several applications in the same fastcgi server on different URLs.

Now try running the script and browse to your site, our sample MVC site should appear!

The last step is to create a upstart script to have our application start automatically at system boot

/etc/init/mvc.conf:

#!upstart
description "sionmailer web"
author      "peter"

start on startup
stop on shutdown

respawn

script
    echo $$ > /var/run/mvc.pid
    exec sudo -H -u peter /home/peter/startmvc 2>&1
end script

pre-start script
    echo "[`date`] (sys) Starting" >> /var/log/mvc.sys.log
end script

pre-stop script
    rm /var/run/mvc.pid
    echo "[`date -u +%Y-%m-%dT%T.%3NZ`] (sys) Stopping" >> /var/log/mvc.sys.log
end script

Save the config file and start the site: service mvc start.

All done, your site is being served by nginx/fastcgi-mono-server4!

Step 1 – Create project
Create a new ASP.NET MVC 3 project. Compile and run it.

Step 2 – Add assemblies needed by Mono
Add references:
System.Web.WebPages
System.Web.WebPages.Deployment
System.Web.WebPages.Razor

Step 3 – Copy local
Make sure to set “Copy Local” to True for all of the following assemblies:
System.Web.Helpers
System.Web.Mvc
System.Web.Razor (C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies\System.Web.Razor.dll)
System.Web.Routing
System.Web.WebPages
System.Web.WebPages.Deployment
System.Web.WebPages.Razor

Remove Entity Framework and other unnecessary assemblies.

Step 4 – Publish your site
Publish it to a directory and copy it to your Linux server

Step 5 – Get latest Mono and compile it from source
I run Ubuntu 11.10 on my server. Ubuntu has Mono 2.10.6 in its repository, which is quite new, but Mono is moving so fast so I recommend getting the latest version and compiling it from source. The latest version at the time of writing is 2.10.8. Nathan Bridgewater has created a script to simplify this process, if you are running Ubuntu, this is what you will need to run to install Mono:

mkdir mono-2.10
cd mono-2.10
wget --no-check-certificate https://github.com/nathanb/iws-snippets/raw/master/mono-install-scripts/ubuntu/install_mono-2.10.sh
chmod 755 install_mono-2.10.sh
./install_mono-2.10.sh

It will take a while to compile it, so now is the time to go grab a cup of coffee.

Step 6 – Run your site with xsp4
Mono have a development web server called xsp4, the first thing we are going to do is to run our site in xsp4 to make sure it works. Mono has been installed to /opt, but does not exist in our PATH, so before we can run Mono we need to setup the mono enviroment variables. To do that I found a script somewhere on the internets, monoenv.sh:

MONO_PREFIX=/opt/mono-2.10
export DYLD_LIBRARY_FALLBACK_PATH=/lib:
export LD_LIBRARY_PATH=/lib:/opt/mono-2.10/lib:
export C_INCLUDE_PATH=/include:/include
export ACLOCAL_PATH=/share/aclocal
export PKG_CONFIG_PATH=/lib/pkgconfig:/lib/pkgconfig
export PATH=/bin:/opt/mono-2.10/bin:$PATH

At your bash prompt type: source monoenv.sh

Now cd into the directory where you have your published web site and run xsp4.

Now your MVC site should be up running on Mono!

In my next blog post I will cover how to configure your site to run using Nginx and the fastcgi-mono server.

+ Amazing screen
+ Good batery life for being a smart phone
+ Really beautiful
+ User interface is blazing fast
+ Integration with Google, Facebook and MSN works great. All my contacts was synced from Google.
+ Fast web browser, zooming and scrolling is super smooth
+ Live tiles are really cool, but not sure if it is the best use of space
+ Hubs! This is a great concept, messages goes to the messages hub, music to the music hub and so on.

- The lack of applications, good thing i am not a big app user
- Applications are not as mature as on iOS or Android. For example the Facebook application is missing a lot of functionality found on iOS and Android.
- The default search engine is Bing and I can’t find a way to change it.
- Navigating back in the web browser. Navigating back to the previous page is done by clicking the back button in the bottom left corner, works great if you are surfing some pages, but if you leave the browser and come back, the back button will take you back to the main screen (or where you were before going back to the web browser). At this point there is no way to navigate back in your surfing history, really dumb!

But over all I must say I am very happy with it!

Let’s imagine that we are writing a small nonsense program. The program receives a post, create some variable x, if some condition is true we call an async method to get some result and assign it to x.result. In the end we want to save x (also async). This would probably be my first attempt in node:
 

(Edit: To clarify, both someOperation and save is doing some kind of I/O)

So is this clean code? In my opinion it is not. One problem is that we have the save code in two places. Another is that the code is not very easy to read and understand (remember this is a very simple program and so should the code), but it is not. Sure we could move it to a separate function, or refactor it in some other way, that would help some, but if we are still saving in two places, or the code is not crystal clear, we are not really addressing the problem.

Let’s instead pretend that we are using synchronous methods (which of course would be a very bad thing in Node.js, so don’t do it) and save are methods that would block:
 

 
To me this is much cleaner and easier to read, saving is only done in one place and the intent of the code is very clear. But why is it so much easier to read? Being synchronous? I wouldn’t say so. The reason is because we do not have to deal with verbose callbacks. In my opinion callbacks are polluting the code. So now you are probably thinking, how can he be programming in Node if he doesn’t like using callbacks? I would say that, at least for the small applications i have build on Node so far, the benefits of simplicity and development speed on Node has totally justified using Node. Even with all the horrible callbacks However, in a larger application I am not so sure, it would be very interesting to try out.

So is there anyway we can get rid of the verbose callback syntax? Yes, if some modifications were made to Javascript. But Javascript as a language is not really evolving that fast, so in the meantime it could probably be implemented in a language that compiles to Javascript, like CoffeScript. What we want to do is to be able to do is asynchronicity, but without callbacks. In C# 5 there is a great solution to this problem, the async/await keywords. By using async/await the application could be implemented something like this (pseudo code warning again):
 

 
In short, async tells the compiler that the above method is asynchronous and await will suspend execution of the method until someAsyncOperation is done.

So the above example behaves in exactly the same way as the first example, but with the benefits of the second. In the background a lot of magic is used to construct this behavior, but this is something that the compiler will take care of for us and we don’t have to pollute our code with.

If something like this would be available for Javascript I think it would really make life a lot easier for a lot of Node.js developers. Maybe there is a good solution to this and I am not aware of it (I am far from a Javascript or Node.js expert), if so please enlighten me!

How do you handle flow control in your Node.js applications? How would you have written the example? Any Node.js magic I am missing?

On the MongoDB web site they have pre built binaries of MongoDB for almost every platform, i grabbed the 64 bit binary for OSX. No installation is required, just unzip the file and run the “mongod” binary from the directory. There is also a binary called “mongo”, this is the mongo interactive shell which is very useful.

The C# drivers are available, both in binary form and as source, from the C# language center. To get started I fired up MonoDevelop 2.8 running on Mono 2.10.8:

MonoDevelop has matured a lot since I used it the first time. It is still not as good as Visual Studio, but it is getting there. What takes most time to get used to is the totally different set of shortcuts, and the lack of all ReSharper magic.

Let me break down a simple console application example on how to use MongoDB using the official driver from 10gen:

If you type this in the MongoDB shell, you will see that the following articles are stored in the database:

> db.articles.find()
        {
          "_id" : ObjectId("4f097f8e74b5b343b97f56a7"),
          "title" : "A MongoDB article",
          "status" : "published",
          "tags" : [ "c#", "mongodb" ]
        }

        {
          "_id" : ObjectId("4f097f8e74b5b343b97f56a8"),
          "title" :
          "A Mono article",
          "status" : "draft",
          "tags" : [ "c#", "mono" ]
       }

Output from the program:

id: 4f0989fc74b5b3458ae38105, title: A MongoDB article
- tags: c#, mongodb
id: 4f0989fc74b5b3458ae38105, title: A MongoDB article
- tags: c#, mongodb
id: 4f0989fc74b5b3458ae38106, title: A Mono article
- tags: c#, mono
Nr of pubhlished articles before update:2
Nr of pubhlished articles after update:3
MapReduce result:
{ “_id” : “c#”, “value” : { “count” : 3.0 } }
{ “_id” : “mongodb”, “value” : { “count” : 1.0 } }
{ “_id” : “mono”, “value” : { “count” : 2.0 } }
{ “_id” : “mono-develop”, “value” : { “count” : 1.0 } }

Using the C# driver for MongoDB, is as you can see, very straight forward. Usually when I run applications on Mono I make sure to build all libraries using the Mono compiler, to make sure the Microsoft compiler have not used any optimizations that is not supported under Mono (I have run into this issue in the past). However, in this case the .NET binaries on the MongoDB site seems to work just fine under Mono. I also downloaded the MongoDB C# driver source and build them using MonoDevelop without any problems.

One improvement I would like to see is LINQ support in the driver. It would be so much more convenient to be able to use LINQ and strongly typed objects to query the database or create MapReduce-functions.