Technology Explained: How Does Facebook Work? The Nuts and Bolts

Social networking is the art of connecting with those who share common interests. Your 'network' is a community that helps keep you united with others and offers many benefits. Networking via social media sites has revolutionized how we use the Internet and is at the forefront of what we now call Web 2.0.

Facebook is social networking. People have been "facebooking" each other for about 6 years now, makingFacebook the most used social network with over 350 million users worldwide. But how does Facebook work?

In this article, I will discuss Facebook's inner workings, covering its architecture and frontend/backend infrastructure—the nuts and bolts that hold Facebook together.

How Does Facebook Work?—The Front End

Facebook uses a variety of services, tools, and programming languages to make up its core infrastructure. At the front end, their servers run a LAMP (Linux, Apache, MySQL, and PHP) stack with Memcache. Not a computer science expert? Let's take a look at exactly what that means.

Linux & Apache

This part is pretty self-explanatory. Linux is a Unix-like computer operating system kernel. It's open source, very customizable, and good for security. Facebook runs the Linux operating system on Apache HTTP Servers. Apache is also free and is the most popular open source web server in use.

MySQL

For the database, Facebook utilizes MySQL because of its speed and reliability. MySQL is used primarily as a key-value store as data is randomly distributed amongst a large set of logical instances. These logical instances are spread out across physical nodes and load balancing is done at the physical node level.

As far as customizations are concerned, Facebook has developed a custom partitioning scheme in which a global ID is assigned to all data. They also have a custom archiving scheme that is based on how frequent and recent data is on a per-user basis. Most data is distributed randomly.

PHP

Facebook uses PHP because it is a good web programming language with extensive support and an active developer community and it is good for rapid iteration. PHP is a dynamically typed/interpreted scripting language.

Memcache

Memcache is a memory caching system that is used to speed up dynamic database-driven websites (like Facebook) by caching data and objects in RAM to reduce reading time. Memcache is Facebook's primary form of caching and helps alleviate the database load.

Having a caching system allows Facebook to be as fast as it is at recalling your data. If it doesn't have to go to the database it will just fetch your data from the cache based on your user ID.

Downsides to Using LAMP

Facebook has realized that there are downsides to using the LAMP stack. Notably, PHP is not necessarily optimized for large websites and therefore hard to scale. Also, it is not the fastest executing language and the extension framework is difficult to use.

Mike Schroepfer, Facebook's Vice President of Engineering, recently did an interview atEmTech@MIT concerning this. "Scaling any website is a challenge," Schroepfer said, "but scaling a social network has unique challenges."

He went on to say that unlike other websites, you can't just add more servers to solve the problem because of Facebook's "huge interconnected dataset." New connections are created all the time due to user activity.

Facebook has grown so quickly that they are often faced with issues regarding database queries, caching, and storage of data. Their database is huge and largely complex. To account for this, Facebook has started a lot of open source projects and backend services.

How Does Facebook Work?—The Back End

Facebook's backend services are written in a variety of different programming languages including C++, Java, Python, and Erlang. Their philosophy for the creation of services is as follows:

1. Create a service if needed

2. Create a framework/toolset for easier creation of services

3. Use the right programming language for the task

A list of all of Facebook's open source developments can be found here. I will discuss a few of the essential tools that Facebook has developed.

Thrift (protocol)

Thrift is a lightweight remote procedure call framework for scalable cross-language services development. Thrift supports C++, PHP, Python, Perl, Java, Ruby, Erlang, and others. It's quick, saves development time, and provides a division of labor of work on high-performance servers and applications.

Scribe (log server)

Scribe is a server for aggregating log data streamed in real-time from many other servers. It is a scalable framework useful for logging a wide array of data. It is built on top of Thrift.

Cassandra (database)

Cassandra is a database management system designed to handle large amounts of data spread out across many servers. It powers Facebook's Inbox Search feature and provides a structured key-value store with eventual consistency.

HipHop for PHP

HipHop for PHP is a source code transformer for PHP script code and was created to save server resources. HipHop transforms PHP source code into optimized C++. After doing this, it uses g++ to compile it to machine code.

Conclusion

In a nutshell, that's Facebook. This article could easily be 37 pages longer if I were to go into more detail, but to answer the question "How does Facebook work?" I think this will suffice. If you look past all of the features and innovations the main idea behind Facebook is really very basic—keeping people connected. Facebook realizes the power of social networking and is constantly innovating to keep their service the best in the business.

FarmVille Surpasses 80 Million Users

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FarmVille, the massively popular Facebook game, surpassed 80 million monthly active users this week (source: AppData). Facebook has around 400 million users in total.

FarmVille has been a breakout hit, with its active user count growing by around 10 million users per month. Note that this isn't simply signups: This is a count of people using the app at least once in the 30-day span.

FarmVille's daily active user count is currently 29.7 million — that's almost 30 million people using FarmVille every day.

FarmVille's parent company, Zynga, was valued at 1 billion dollars late last year.

HOW TO: Block FarmVille on Facebook

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The Facebook-platform game FarmVille has 80 million players. It's been named social networking game of the year. It's played by people young and old. It's bigger than Twitter. But that doesn't mean it's for everyone.

The game optionally advertises itself by sending out news feed updates to your friends whenever you accomplish a milestone with your farm or character. When you have lots of friends playing FarmVille, those updates can be ubiquitous enough to drive you a little crazy.

Here we'll save your sanity by showing you how to hide all those FarmVille news feed updates and notifications without burning any bridges with your passionate social gamer friends.

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Hiding Friends' FarmVille News Feed Updates

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This task is simple. Any time you see a FarmVille update in your news feed, move the mouse cursor to the right of the update and a "Hide" button will appear as seen above. Click on it.

As illustrated above, you'll then be given the choice to either hide that friend or just the FarmVille app. Since you probably want to keep seeing your friend's updates (we hope), click "Hide FarmVille." This will hide FarmVille news feed posts from all your friends, not just the one who published that particular update.

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Blocking FarmVille Notifications

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Sometimes friends will send you notifications inviting you to join them in FarmVille or other games. These can be annoying if you're not interested in playing. The easiest way to take care of this is to click the "x" next to the notification when you receive to block the FarmVille application.

But if you want to do this preemptively without waiting for another notification, just search for the FarmVille application using the Facebook () search bar, go to the application page, and look for the "Block Application" link directly below the application image. We've included a pic above so you'll know what you're looking for.

Clicking that and confirming will prevent FarmVille from accessing your information or sending you notifications, but it won't hide news feed updates from friends.

[via mashable]

Fly By – Pakistan’s First Flash Game on Facebook

As spotted by CodeWeek, Fly By, Pakistan's first Flash Game has ultimately appeared on Facebook, and already  it has attracted more than 800 users from all over the world.

Fly By is developed by Web Sketchers, a team of individuals who graduated from FAST-NU Lahore in 2009.

The game is visually spectacular, rich in colors, and encompasses eye-catching 3D modeling.

The basic theme of the game is the flight of an aircraft through the city centre. The aircraft is flying low, and has to evade the numerous skyscrapers and hot air balloons that encroach in its path. The player has to maneuver the aircraft through these obstacles. As the player progresses, points are earned and newer levels of play are attained during game play.

Web Sketchers say they are going to add more features in coming days, based on users' feedback.

Web Sketchers also intends to launch a number of new and exciting games in the near future under the umbrella of brand "Wesga".

Link on Facebook to play: http://apps.facebook.com/flybygame

Convert RPM to DEB in Ubuntu

Many Linux distributions use .RPM files, like Red Hat and Fedora.
There is a great program to convert RPM's into DEB's, Alien.

 

To install Alien, Go to Terminal and type

sudo apt-get install alien

Once installed, you can convert the RPM file like:

sudo alien -k FileName.rpm

To then install the DEB file, you can either double click on it or run the command:

sudo dpkg -i FileName.deb

Or another way to convert and then install straight after, you can run the following command:

sudo alien -i FileName.rpm

source

Windows Activation Technologies for Windows 7 Update Available

We have covered the news about the Windows Activation Technologies for Windows 7 update earlier this month with the expectation that Microsoft would provide downloads for the update later in that month. The first step has apparently been made as a Knowledgebase article now links to the update that can be downloaded for 32-bit and 64-bit Windows 7 computer systems.

The update basically improves the capabilities of the Windows 7 operating system to spot activation hacks that have been used to activate the operating system without a purchased product key.

Windows Activation Technologies helps you confirm that the copy of Windows 7 that is running on your computer is genuine. Additionally, Windows Activation Technologies helps protect against the risks of counterfeit software.

The update is currently only offered on the Microsoft website but will be added to Windows Update at a later time. It will however be an optional update in Windows Update as well for the time being which means that it only serves the following purposes:

• Provide the ability for users who have bought a computer system with Windows 7 or Windows 7 standalone to verify that their product is genuine and not counterfeit.
• Provide the ability for hackers to find out if their activation hack is still working

Users who have illegally activated Windows 7 will obviously not install and run the Windows Activation Technologies for Windows 7 update as they might risk getting it flagged as non genuine.

It will be interesting to see if and when Microsoft decides to make the update mandatory for all Windows 7 operating systems.

[via ghacks]

Mobilink’s Blackberry Stock Clearance Loot Sale

Looks, Mobilink want to clear its stock – by all means. For the purpose, they are offering plenty of discounts on Blackberry handsets.

Earlier, Mobilink offered 30 % Discount on all Blackberry Storm smarphones, if bought online – and now the offer got even better.

Despite, the fact that Blackberry Storm didn't click the market, Mobilink's this loot sale is pretty impressive. Following are three offers you can choose from!

BlackBerry® Pearl™ Free with Blackberry Storm

The BlackBerry® Pearl™ is offered free of cost, if you buy a Blackberry Storm, till the stocks last.

BlackBerry® Pearl™ with 40 % off!

The BlackBerry® Pearl™ 8110 and Pearl 8120 both have discounts on them of 40%! This offer is only till stocks last.

BlackBerry® Storm™ with 30% off!

BlackBerry® Storm™ smartphone is available from Mobilink with 30%! This offer is only till stocks last

To avail this offer click this link and fill the form: http://www.mobilinkgsm.com/indigo/bb_offer.php

via propakistani

Google's Facebook

First they challenged the likes of RIM, Apple and Nokia, and now they are up against Facebook and Twitter. By all means and in all sanity Google has launched its social networking website by name Google Buzz. This was done on February 09, 2010.

Buzz offers a stream of status updates, pictures, links, and videos from your friends. You can "like" these items and you can comment on them. Updates from Flickr, Picasa, Google Reader, or Twitter can also be automatically imported into a Buzz stream. Buzz will recommend items you might like based on your friends' activity.

But the question that counters the world is: will it outdo Facebook and Twitter? Let's see how Microsoft answers this:

"Busy people don't want another social network, what they want is the convenience of aggregation. We've done that. Hotmail customers have benefitted from Microsoft working with Flickr, Facebook, Twitter and 75 other partners since 2008."

Mostly biggies leave all this stuff for the blogger community and Press but this time Microsoft went ahead to fight at the front.

The edge which Buzz will have over Facebook and Twitter is the existence of Google's own mobile world.

http://buzz.google.com ;)

via [Zumbeel news]

Google Buzz in Gmail

Five years ago, Gmail was just email. Later we added chat and then video chat, both built right in, so people had choices about how to communicate from a single browser window. Today, communication on the web has evolved beyond email and chat — people are sharing photos with friends and family, commenting on news happening around them, and telling the world what they're up to in real-time. This new social sharing is valuable, but it means there's a lot more stuff to sort through, and it's harder to get past status updates and engage in meaningful discussions.

Today, we're launching Google Buzz, a new way to start conversations about the things you find interesting and share updates, photos, videos and more. Buzz is built right into Gmail, so there's nothing to set up — you're automatically following the people you email and chat with the most.

We focused on making the sharing experience really rich by integrating photos, videos, and links. No more fuzzy little pictures: Buzz makes it easy to quickly flip through photos and experience them the way they were meant to be seen: big and full-resolution. And videos play inline so you can watch them without opening a new window.

You can choose to share publicly with the world or privately to a small group of friends each time you post. And you can connect other sites you use, today there's Picasa, Flickr, Google Reader, and Twitter, so your friends can keep up with what you're doing around the web — all in one place.

To make sure you don't miss out on the best part of sharing, Buzz sends responses to your posts straight to your inbox. Unlike static email messages, buzz messages in your inbox are live conversations where comments appear in real time.

You can follow the specific people whose posts you want to see, but Buzz also recommends posts from people you're not directly following, often ones where your friends are having a lively conversation in the comments. If you're not interested in a particular recommendation, just click the "Not interested" link and your feedback will help improve the recommendations system. Buzz also weeds out uninteresting posts from the people you follow — collapsing inactive posts and short status messages like "brb." These early versions of ranking and recommendations are just a start; we're working on improvements that will help you automatically sort through all the social data being produced to find the most relevant conversations that matter to you.

For all those times when you want to share something but aren't in front of your computer, Buzz is also available on your phone. When you're out in the real world, a lot of the information you want to share often has to do with where you are: for example, you may want to talk about a new restaurant you discovered or the score of the game you're watching. So rather than simply a small screen version of the desktop experience, Buzz for mobile brings location to the forefront and makes it easy to have conversations about places. In addition to checking out buzz from people you're following, you can also see nearby buzz from the people around you.


We'll be rolling out Google Buzz to everyone over the next few days; you'll see a new "Buzz" link under "Inbox" when it's on for your account. We're still working on some features to make Buzz work well for businesses and schools, so it isn't yet available in Google Apps, but stay tuned. If you want to learn more in the meantime, visit buzz.google.com

Wireless Network Scanner inSSIDer

The wireless network scanner inSSIDer can be used to quickly scan the area for wireless networks. The software program works well with Windows Vista and Windows XP (even the 64-bit editions) and can quickly display all wireless networks in the vicinity. A network adapter has to be selected to start the scanning. All discovered wireless networks are then added to a table in the same interface which lists information like their MAC address, SSID, channel, security and network speed.

Graphs are shown below the table that visualize the signal strength of the selected wireless networks over time. It is possible to select some or all of the wireless networks and observe their performance.

The visualization can help the user troubleshoot the wireless network. It could for example be that all or most of the wireless networks in the area are concentrating on specific channels for the communication. It could then help to switch to one of the transmission channels that are the least used in the area to improve the speed and performance of the wireless network.

InSSIDer is an Open Source software program that might be useful for users who want to troubleshoot, optimize or configure their wireless networks. Beta 1.2 of the program has been released a few days ago and is available for download on the developer's homepage.

Very Simple Network Scanner

A network scanner is a program that can scan a specific network IP range for devices. This can be interesting for maintenance or inventory related tasks as well as network monitoring and retrieving information about a specific device in the network.

Very Simply Network Scanner is a free software program for the Windows operating system that can scan a network range. The main purpose of the program is to scan a specific network range, display a list of devices discovered in that range and provide the means to export the findings in a csv file.

The network scanner is relatively easy to use. The network IP range can be selected in the network field. The first three digits of the IP are left untouched but the last digit defines the starting point of the scan. The end point of the scan is the last possible digit in that range (e.g. from 0 to 255).

A click on scan network will initiate the network scan which does not take longer than a few seconds usually unless the network utilizes many devices on different IPs.

Each device will be listed with its IP, DNS, time and TTL, Mac address and device type among other parameters.

Selected information can be copied to the clipboard. The user of the program can select the device type by right-clicking on a line in the results which makes identification of devices easier.

A port scanner is included that can be used to retrieve the ports that are open by the selected network IP.

Very Simple Network Scanner is a work in progress. The portable software program is currently offered as an alpha version that can be downloaded from various software portals like Betanews.

Recover Operating System After Virus Attack

One of the problems that many computer users experience after a computer virus attack are changes to the system cause by the malicious software. This can for instance mean that system tools like the control panel or task manager do not open, that security permissions have changed, services or startup items have been added or modified or that processes run in the background that have been loaded by the virus.

It is sometimes impossible to fix the damage done to the system which means that in those cases only backups or new installations are an option. But most changes are not as severe. They can be fixed either by the antivirus software cleaning the malicious program or by a third party tool like Virus Effect Remover.

We have reviewed Virus Effect Remover in the past but it has evolved since then which is reason enough to take a new look at it.

The software is a specialized tool which becomes apparent after startup. There are lots of buttons and information displayed in the main interface from access to tools in the left sidebar to a tab driven interface that displays a processes tree and links to various tools that can be used to check and repair specific system settings, files and features.

The tools on this page allow a user for instance to scan services, startup locations, check system files, show suspicious files, generate a process list and about a dozens of others. And that only from the main tab.

The other tabs list autorun details, process details, files and folders options, unlocker, other tools and options. Some of those, like the files and folders options display another tab bar below which demonstrates the complexity of the program.

Virus Effect Remover links to various Microsoft Windows system tools like the Registry Editor, Group Policy Editor or MSConfig.

The program provides the user with many useful information about the operating system and controls to repair some of the damage that has been done by a computer virus.

Backup Your Gmail, Hotmail, Facebook, Wordpress, Twitter and More, Fore FREE

Just seconds ago, Dr. Awab tweeted that he took backup of his blog, and downloaded almost 1 GB of files on local computer. Just that moment, a co-incidence maybe, I was reading this post by CyberDera about taking online backups of almost every online activity that we usually do – for FREE. Yes, this very amazing service Backupify, is offering backups for Wordpress, Gmail, Hotmail, Flickr, Facebook, Twitter, Blogger, Google Docs and what not. Essentially, for every internet user – they are offering something to backup – and for expats, this is a one stop platform to backup all your online accounts. If you are using Wordpress, stop worrying about backups, as this cloud based backups are automatic, seamless and are free (only if you sign-up before February 15th). Backupify will keep a copy of your database (.sql file) and blog files separately, that you can access anytime in future. Though it's very rare, but we have seen instances of Gmail accounts vanishing and then never appearing back. If you find your emails very crucial, which I suppose they are, you can add your gmail account as well, to download latest copy of your Gmail data. And all this comes with extremely easy to manage interface. Usually it doesn't take more than few clicks to add an account for taking backups. Based on cloud storage, you need little to worry and there are almost no chances that Backupify will lose your backups. They are using Amazon's S3's secure and reliable services. Also to mention, all files are stored with secure keys – so that no one can access them. If you have your own S3 storage account, you can configure it with Backupify to use your space. Backupify is offering free sign-up till February 15, 2010, and will remain free who are signing up now. After this date two variants of premium accounts (49$ per year and 79$ per year) will be available, which I find very attractive – with what they are offering. Click here for Backupify FAQs.

YouTube Banned on Selected ISPs, Update: YouTube is Back, Except Some Videos

We have received multiple confirmation from various sources that YouTube has been banned in Pakistan, at least on some ISPs.

We are checking ISPs and authority for any official word on it. We will update this story, when and if we get anything further in hands.

Update: YouTube is back. We are told by sources that during filtering policy update, YouTube got banned by mistake. We are yet to get any official word from PTA.

Website remained down for at least 40 minutes.

Update 2: Looks, not all of YouTube got back, as President Asif Ali Zardari's recent videos are still restricted. So, apparently the puzzle has been solved.

We will update this post, when and if we get any word from PTA or ISPAK.

via [propakistani]

Chat with Any Mobile in Pakistan using MSN Messenger!:SMS Live Pakistan

Introduction MSN provides service to chat with your SMS contacts in a few countries, like USA, Brazil and UK. This service is not available in many countries including Pakistan. MSN Messenger Mobile Service Pakistan is a free service that enables people to chat with their mobile contacts in Pakistan, no matter which service provider they might be using. System Requirements Windows XP/2000/2003/Vista (latest service packs recommended for all Operating Systems). Internet Connection (broadband recommended). Windows Live Messenger 2009. Download Installation You are required to download and install the service client which will automatically install the required pre-requisites. Download and unzip the archive and execute the setup.exe MSN Messenger Mobile SMS Service Client Download Configuration Configuring MSN Messenger is very simple. Just follow these three steps: Sign-out MSN Messenger. Run the client application. Sign-in MSN Messenger.

	Sponsors

	How to use? After the installation and configuration, the SMS capabilities of your Live Messenger will be activated for Pakistan. If you are diconnected from the service, sign-out and sign-in again to get connected. You can now add an SMS Contact and chat with them normally. In Windows Live Messenger 2009 click the Contacts > Add a contact menu item. Only provide the mobile number you wish to chat with and select the country Pakistan and click next. The mobile contact will start appearing in your list. In case the contact does not appear at first, repeat step 1 and 2.     Just double click the SMS contact and start chatting.

	Sponsors

	Trouble-shooting MSN Messenger Mobile SMS Service for Pakistan is a free service. This service will become more and more reliable in the coming days. If you are facing difficulty trying to use this service please see the following common issues. If you are unable to solve your problem please contact us at info@smslive.pk Look for the mobile icon in your system tray. If you cannot see any such icon, may be you forgot to run the client or donot have enough previlleges on your machine. Are you connected to the MSN Messenger Mobile SMS Server? The icon in the tray turn Red if the server cannot be connected. If the icon is Green, please revisit the How to Use section of this page.     If you are not connected to the server, please run the connectivity test Tools > Options > Connection > Advanced Settings > Test (SOCKS). If this Test is successful, please sign-out and re-sign-in the MSN Messenger. If the test fails, report this occurance to info@smslive.pk via email OR add admin@smslive.pk in your MSN Contacts to get LIVE help.

How to Install BitDefender in Ubuntu

BitDefender is a program to check for Windows viruses and malware. It can be run in the background or on demand when required. Once installed it can be found under Applications - Systems Tools. It can be used as an alternative to clamav/clamtk.


Installation

Add the repository by going to System -> Administration -> Software Sources and click on the 'Third

Party Software' tab. Now click on 'Add' and copy+paste the following line:
deb http://download.bitdefender.com/repos/deb/ 

bitdefender non-free

Click on 'Close' and press 'Reload' when prompted. Ignore the 'No repository key' error (if displayed). To add the repository key open a Terminal (Applications -> Accessories -> Terminal) and copy+paste the following lines::

wget http://download.bitdefender.com/repos/deb/bd.key.asc
sudo apt-key add bd.key.asc

Now update the sources list:

sudo apt-get update

To install the graphical interface and command line program copy+paste the following line:
sudo apt-get install bitdefender-scanner-gui

Once complete you now need to log out and log back in again. a menu shortcut will be generated (Applications -> System Tools -> BitDefender Scanner).

Before running the scanner it's probably best to install the latest virus/malware signatures by clicking on the 'Update' button.

License

BitDefender comes with a standard 30 day free license, when first installed. It is free for private and personal use - the license can be extended to one year by requesting a new license key fromhttp://www.bitdefender.com/site/Products/ScannerLicense/ For all business use a paid for license is required.

[Via link]

Enable Automatic Login in Ubuntu 9.10 Server

Ubuntu makes it easy to enable automatic login if youá��re using a login manager such as GDM. I was recently setting up a minimal Ubuntu 9.10 system with an LXDE desktopand no GDM. Hereá��s how I enabled automatic login.

Note: This was tested on Ubuntu 9.10. Previous versions of Ubuntu require different procedures because of changes to the way Ubuntu boots.

Open /etc/init/tty1.conf as root:
sudo nano /etc/init/tty1.conf

Change the last line of this file to (where USERNAME is the username of the user you want to log in):
exec /bin/login -f USERNAME < /dev/tty1 > /dev/tty1 2>&1

Reboot, and the user you chose should be logged in automatically after boot. If something goes wrong, you can switch to a different TTY with CTRL+ALT+F2 and log in normally.

If you want this user to be logged into a graphical environment instead of just a shell, thereá��s more work to be done. Open your userá��s .bashrc file:
nano ~/.bashrc

Add the following to the end of the file:
if [ $(tty) == "/dev/tty1" ]; then
startx
fi

This code will start X (the graphical environment) whenever the user logs in on TTY1. You can add more code after startx that will be executed if the user logs out of X.

[Via Link]