How To Solve the Rubik's Cube

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How To Solve the Rubik's Cube
Solve 3x3 Rubik's Cube Top Edge Cubies
Solve 3x3 Rubik's Cube Top Corners
Solve 3x3 Rubik's Cube Middle Layer
Solve 3x3 Rubik's Cube Form a Cross on Last Layer
Solve 3x3 Rubik's Cube Correct Corners on Last Layer
Solve 3x3 Rubik's Cube Orient Corners on Last Layer
Solve 3x3 Rubik's Cube Correct Edges on Last Layer

Get a Rubik's cube or a Rubik's cube solving guide on

Play with the cube by clicking and dragging it!!!

A 3x3 Rubik's cube has 6 faces, each consisting of 9 little squares. Each square has a color out of 6 colors. You can rotate any side and the goal is to make every side have the same color.

This tutorial teaches you EXACTLY how to solve the Rubik's cube. It is one of the easiest rubiks cube solutions. There are many websites on solving a Rubik's cube, but it's so DIFFICULT to find one that tells you exactly how to solve it from start to finish Most them either brag about their achievements or their awards or tell you part of how to solve it. I was very upset. Now that I know how to solve the rubiks cube, I am determined to write a post about it so anyone interested in solving a Rubik's cube can learn how to do it in a matter of hours.

Let's get our terms synchronized before moving on.

A cubie is the little cube in the Rubik's cube. A 3x3x3 Rubik's cube, for example, has 27 cubies.
A Face, depending on the context, can mean a Rubik's cube's face or a cubie's face. However, "...on red face..." would refer to the Rubik's cube's red face.
A square, depending on the context, can mean a side of a cubie or that of a cube's face
An edge cubie is a cubie that sits on some edge of the Rubik's cube
A corner cubie is a cubie that sits on some corner of the Rubik's cube

Play with the Rubik's cube and you should be able to observe the following properties of the Rubik's cube:

The centered square of any face is fixed, meaning that the color of the face must match the color of the square at the center.
Every cubie belongs somewhere, and somewhere only. For example, an edge cubie consisting of color green and blue belongs to the edge between green face and blue face.
You can find numerous instances of symmetry while solving the Rubik's cube. The examples I show might not cover all absolute cases, but they should cover all symmetrical or mirror cases. So if you don't see the configuration you need at first look for the symmetrical configuration.

Remember the above properties as well as you can. Repeat them in your mind several times. You cannot proceed without knowing those properties.

An algorithm is a sequence of moves you do on a Rubik's cube in order to go from one configuration to another. An algorithm is represented in this format:
[letter][special symbol or empty] [letter][special symbol or empty] ...

[letter]: It represents the face you rotate. The following is a list of possible values and what faces they represent:

* L - left face
* R - right face
* U - top face (up)
* D - bottom face (down)
* F - front face
* B - back face

[special symbol or empty]:

* [empty] - rotate clockwise once
* 2 - rotate clockwise twice
* ' - rotate counterclockwise once

For example, "L R' U2 D F B" means "rotate left face clockwise, rotate right face counter-clockwise, rotate top face clockwise twice (same as counter-clockwise twice), rotate bottom face clockwise, rotate front face clockwise, rotate back face clockwise." I will be speaking in these terms when I describe an algorithm. So you MUST know these terms before moving on.

The orientation of the Rubik's cube you see when the webpage finishes loading is the orientation we use. It should be straightforward where "left", "right", "front", "back", "top", and "bottom" are. If you rotate the Rubik's cube with your mouse, you need to refresh the webpage in order to have the Rubik's cube revert to the original orientation.

In the examples I show, I only show colors for relevant cubies and leave the rest cubies gray. Also, to be consistent, the front face in my examples is always red.

You might be confused as to what direction "clockwise" and "counter-clockwise" refers to. Play with the following Rubik's cube by pressing the Play button. It represents the algorithm "L L' L2 R R' U U' D D' F F' B B'". Familiarize yourself with the buttons in the animation and drag your mouse on the cube to get a feel for it. It should be pretty straightforward how it works. NOTE If you see no animations below let me know!




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How To Remove Virus From Computer on Windows

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Identify Virus Process
Stop Virus Process
Delete Virus Files
Stop and Kill
Protect Your Computer
FAQ

Many people have frustrating experiences where their PC is infected with computer virus, and they need tools for virus removal. If they are technical, they might try to remove virus themselves only to make it worse. Otherwise they may buy and use antivirus software and successfully remove the virus. You can browse a list of great antivirus software on . So I am putting together this post to help people remove virus from computer. Note this is strictly for computers that have Windows operating system on them. I am no expert myself but with a computer science background and expertise in how computers work, I believe I'll cover the topic well. Also, I've helped my relatives remove computer virus that cannot be killed by antivirus software. It's truly FREE virus removal Learn it and you'll be able to remove virus or any trojan and spyware.

Before we jump into discussing how to remove virus from computer, Let's get some definitions straight first:

A computer virus is simply a computer program that does bad things to your computer.

A virus process is the running instance of a virus. If the purpose of the virus is to pop up ads, it will do that at some time intervals (e.g. every 5 minutes) or it is triggered by some action on your part (e.g. close a Internet browser). If the purpose of the virus is to delete everything on your C drive, then it will do that the first chance it gets, and you will need to reinstall your operating system. Talking about frustrations

A virus file can be any file that contains the virus. Most commonly the file is a Windows executable (a file that ends in .exe) or a dynamic linked library (a file that ends in .dll). This is the file you want to delete to remove virus.

Note that the core system DLLs are stored in C:\windows\system\ and C:\windows\system32\. In general you shouldn't see any new DLLs being added to the folder, unless you install software. In general viruses lives in one or both of these folders.

Before you do anything, download Process Explorer (Google it). It is informative about the processes that are currently running on your computer. All you have to do is double click the executable to run it. When you run it, you need at least the following columns: PID, Command Line. If you don't see any of them, right click on the column bar and choose "Select Columns..." Then check the columns you want and click OK.

If you run antivirus applications such as McAfee or Norton, you can run it and they probably can scan your computer for viruses and delete them. Or you may see a pop-up window saying a virus is found and what you want to do with it. The trouble is sometimes they say that the virus is found but they are unable to delete it That just adds insult to injury. This is most likely due to the fact that the virus process is already running, and therefore you cannot modify any file that the virus process depends on. Sorry, operating system rule..

Here's what I suggest you do to remove computer viruses

* Identify virus process
* Stop virus process
* Delete virus files, and sometimes Stop and kill
* reboot your machine
* Protect your computer
* FAQ

Without further ado let's get right down to killing those nasty computer viruses!

Identify Virus Process ▶

How To Identify Computer Virus Process

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First of all you can get antivirus software on if you want quick results. Otherwise read on.

So how do you know if a process is virus? If your anti-virus software identifies some .exe as a virus, then you know. If your anti-virus software identifies the DLL the virus is using, then you can find out the .exe using it in command line (FAQ). If not, then there must be something that leads you to believe you have a virus running. In Process Explorer (if you haven't so google and download it!) you can see Company Name. A virus generally doesn't have a value there. Also its process name sounds weird, unlike notepad.exe or iexplore.exe. However there are many weird sounding names that are actually core system processes that must be running. Unless you are an expert you cannot easily tell which process is virus. Here is a list of legitimate processes you shouldn't mess with:

* svchost.exe
* lsass.exe
* taskmgr.exe
* smss.exe
* csrss.exe
* winlogon.exe
* TCPSVCS.EXE
* mdm.exe
* wdfmgr.exe
* usnsvc.exe
* explore.exe
* iexplore.exe

In Process Explorer, you can see the icon next to the .exe and you should know if it's a program you are using right now (e.g. notepad, acrobat reader, internet explorer). Keep in mind that you can stop any process you want even if it is a critical system process, because even if something bad happens, you can reboot your PC and all critical processes will be running again.

You should be able to find the absolute path of the virus .exe by looking at Command Line column in Process Explorer (e.g. C:\WINDOWS\system32\iAmAVirus.exe). However, it is not necessarily the virus .exe; it could very well be a legitimate .exe that the virus dll is hiding from. If that's the case, go to section Stop And Kill.

By now, if you identified .exe only, you may feel bummed that you only found out what .exe is the virus, but don't be. If you kill the .exe successfully, your computer will never run the virus process again, and therefore even if there are bad DLLs lying around, they won't hurt. If you identified .exe as well as the DLLs it depends on, then you can remove them all. You can try to delete them now, but chances are you will see the following error message:



This is because the file you are trying to delete is used by some running process. If this process is the virus process, you can stop it. If this process is actually a legitimate process like explore.exe and winlogon.exe, then you need to handle it with some finesse. You may find it surprising, but a tricky virus DLL can hide behind any legitimate process. If that's the case, go to section Stop And Kill.

◀ HomeStop Virus Process ▶

How To Stop Computer Virus Processes

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First of all you can get GREAT antivirus software on

The goal here is to stop a virus process. Even if you cannot delete virus files, as long as you can stop the process that does bad things, you can proceed with normal work without worrying about virus. You have the following ways to stop a process:

* Configure startup processes to stop it: A process can be run by a service, or it can run by a startup process. If you can identify the service or the startup process, then you can tell your computer not to run if the next time it boots. This is the recommended approach. Sometimes a virus process doesn't start running until several minutes have passed since boot. In this case the virus process is usually run by another process, which could be a legitimate process (e.g. services.exe). Exactly how Windows services work is beyond the scope of this tutorial. All you need to know is that you should find out whether the virus process is run by some Windows service. The quickest way to find out is to count the number of running services after the virus process starts running (by going to Windows -> Run... -> type 'msconfig' and clicking Services tab). You kill the virus process; then count the number of running services again. If the number drops by one, then you know for sure some service is the culprit. Find out what that service is and uncheck it and reboot. I removed a virus for my uncle this way.

First identify the service that runs the virus process Go to Windows -> Run... -> type 'Services.msc'. You should see a list of services. For each of them you can right click and choose 'Properties' (or right click and press key 'R'). In Properties window you can see 'Path to executable', which is what you are interested in. Since you already know path to the virus .exe, you can go through each service and see which one has that path. If you can find it, go to Windows -> Run... -> type 'msconfig'. Click Services tab and you should see a list of services in there. The checked ones are the ones that run automatically when your computer starts up. Uncheck the virus service and reboot.

After your computer boots up, the virus process should not be running and you should be able to safely delete the virus files. HOWEVER, if the service is a critical Windows service such as 'COM+ Event System' and 'Workstation', go to section Stop And Kill. If you cannot find it, go to Windows -> Run... -> type 'msconfig', go through the list in Startup tab. In Command column you can see the path to the .exe. Uncheck the one that matches the path to the virus and reboot. After your computer boots up, the virus process should not be running and you should be able to safely delete the virus files.

* Kill the process manually: right click on the .exe in Process Explorer and select "Kill Process". HOWEVER, if this is a critical Windows process such as 'svchost.exe'. you may see an error dialog saying that you cannot kill it. Or you may kill it successfully but then your computer behaves in a weird, unstable, or inoperable way(e.g. all your items on your desktop are gone if you stop 'explore.exe'). If this is the case, go to Section Stop and Kill. Otherwise, you can safely delete the virus files.

If you can successfully stop the virus process, you will be able to delete the virus files. Again, even if you cannot delete virus files, as long as you can stop the virus process, the virus will not affect your PC and you can proceed with your normal work. Reboot and the virus should be gone. Otherwise, consult Section Stop and Kill.

As an alternative you can rename the virus file to any junk name. The Windows OS does not allow you to delete a file when some process is using the file but it allows you to rename it, rendering it unusable. Once you've renamed it you should be able to delete it

◀ Identify Virus ProcessDelete Virus Files ▶

How To Delete Computer Virus Files

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First of all you can get GREAT antivirus software on

If you have successfully stopped the virus process or renamed the virus file, you should be able to delete the virus .exe and .dll. If you have trouble deleting the .dll (you get a message saying that the dll is being used), find out what process is using it (FAQ), and stop that process if you can. If it's a critical Windows process, consult Stop and Kill. If you just can't figure out what's using that dll and you really want to delete that dll badly, you can reboot your PC in Safe mode (at startup press F8 and pick 'Run Windows in Safe Mode'). In this mode, Windows only loads minimal critical resources to run Windows. You should be able to delete the virus dll in this environment.

◀ Stop Virus ProcessStop and Kill ▶

How To Stop And Kill Computer Viruses

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First of all you can get GREAT antivirus software on

If you need to consult this section, that means the virus is pretty advanced and the creator is smart enough to put it under the aegis of a critical Windows process. But there is always someone smarter, and in this case, me. Here's how I would handle it (In fact, I handled it this way and successfully killed a computer virus for a relative of mine). I use one ampersand-separated command line to do the following things:

* kill the relevant processes
* delete the virus files

You need to do this because the process you want to stop is a critical process, and upon stopping your computer will stop functioning normally. It might even attempt to reboot automatically in a short period of time Your best bet is to delete the virus files then. Since the relevant processes have been stopped, deleting the virus files will be allowed. Here is a sample command (assuming 1212 and 2323 are the IDs of the relevant processes and I am on Windows 2003 Server):

taskkill /f /pid 1212 & taskkill /f /pid 2323 & del /f c:\windows\system32\bad.exe & del /f c:\windows\system32\bad.dll

Of course you can execute each command at a time, but I'd rather execute them all at once. Once it's done, reboot and the virus should be gone.

◀ Delete Virus FilesProtect Your Computer ▶

How To Protect Your Computer From Virus

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First of all you can get GREAT antivirus software on

Obviously you want to protect your computer from getting infected with other viruses in the future. To do that you have at least the following options:

* Subscribe to a Firewall service: Personally I recommend this option. I have been using Sygate, a software firewall, for the past several years and my computer has never been infected with any virus of any kind. You can use other firewall software or even hardware, and it should help protect your computer. In fact, you can use Windows firewall that's already installed on your computer. I never used it before and cannot vouch for its reliability.

* Subscribe to an antivirus software: You can find many decent antivirus software by searching on the Internet, such as Norton, McAfee, avast!, some free and some are not. You can get GREAT antivirus software on Amazon!

Also, you can clean your system's folder periodically. Go to C:\windows\system32\ and C:\windows\system\ and sort by Date Created (FAQ). As I mentioned earlier, you should not see new DLLs added here unless you've installed some software. Date Created column gives you an idea of when the file is created, and you can use your judgment whether you want to delete or keep a DLL. For example, if I knew I didn't any software since 9/1/2007, then I would delete everything created after 9/1/2007. If after you reboot your computer is not running correctly, you can simply restore those files in Recycle Bin and reboot again. If you happen to delete some DLL that some software on your computer needs, simply reinstall that software. There is always turning back

◀ Stop and KillFAQ ▶

FAQ Regarding Removing Computer Viruses

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First of all you can get GREAT antivirus software on

Q: What is an executable?
An executable, or more formally an executable program, is the file that you double click to run whatever program you have installed on your computer. Whenever you install some program, you almost always see a file that ends with .exe, and you double click it to run it. It can be self-contained, meaning that it alone can do everything it's supposed to (you can move it to another computer and run it without any problem), or more commonly, it contains only the core logic of the program, and delegates to other files for other tasks. An example is a DLL. An executable can, for example, calls a DLL to print a document.

Q: What is a dll?
DLL stands for dynamic linked library. A DLL is a collection of programs which can be called by an executable. In general, it contains code for doing something general so that it can be shared by many programs.

Q: How do you view process list?
Download Process Explorer (find it on Google). You can also hit Ctrl + Alt + Delete and click Task Manager. Click Processes tab. You see a list of processes running here. You can sort them by any of the column by clicking the column head. However it doesn't tell you the process IDs.

Q: How do you kill a process?
First find the process ID (pid) in Process Explorer.
windows 2003 server: taskkill /f /pid [pid]
windows XP: kill -f [pid]

Q: How do you delete a file in command line?
windows server: "del /f [path_to_file]"
windows XP: "del [path_to_file]"

Q: How do you view the executables that are using a given DLL?
Windows server: tasklist [path_to_dll]
Windows XP: if you don't already have "tasklist", then download it at http://www.computerhope.com/download/winxp.htm, then the command is: tasklist /m [path_to_dll]

Q: How come I don't see the column inside a folder you are talking about?
In the window, go to View -> Details and you should see the files organized in details. You should see columns like Name, Size, etc. You can manage what you see here by right clicking on any column and checking whatever you want to see and unchecking whatever you don't want to see.

Q: How come you know so many useful software applications?
You can do a search on Google or Yahoo or your favorite search engine. When it comes to searching for software, however, I go to download.com. It allows you to search for any software with any filter you specify, and it is very easy to use


◀ Protect Your Computer

Cross Browser Compatibility Guide

I've had my share of testing and debugging browser compatibility issues, and I'd like to share my experiences with you. I'll also tell you how to test browser compatibilities efficiently.

What extent of cross browser compatibility testing is considered "enough"?

The technical answer is it is never enough not because there are too many browsers but because there are too many versions of each browser and too many possible addons and plugins that can be installed on them. Since we can never catch every fish in the ocean let's just focus on the big ones shall we According to NetMarketShare, roughly

60% use IE (Microsoft Internet Explorer)
25% use Firefox
7% use Google Chrome
5% use Safari

But this data is not enough - You need to know what VERSIONS of each browser you need to test. Again according to NetMarketShare, in the descending order of percentage, roughly

24.5% use IE 8.0
17.5% use IE 6.0
15.5% use Firefox 3.6
12.5% use IE 7.0
6% use Firefox 3.5
5.5% use Google Chrome 4.1
4% use Safari 4.0

Therefore I'd say the extent of testing these browsers is considered enough.


That's still a lot! Any way you can cut the list down?

I totally understand your position, and I can tell you what browsers I test my websites on. I test IE 6.0, IE 8.0, Firefox 3.6, and Chrome 4.1. That's it.

I don't test Firefox 3.5 because the main difference between 3.5 and 3.6 is speed, as Mozilla claims. Therefore there's no much look-and-feel or layout difference between the two. I picked FF 3.6 because it really is much FASTER than 3.5

On the other hand, the main differences between IE7 and IE8 are the new features that IE8 offers. They both comply with DOM Core, DOM HTML, etc. although IE8 complies better with CSS 2.1 selectors and declarations. If you don't use any crazy CSS selector such as :before and :after and :hover and :active then you should be fine. My websites are not that CSS crazy and I can get away with it. If your websites are CSS mad then you need to test both IE7 and IE8.

I don't test Safari because I am using Windows. Lame excuse I know but I used Safari for two years before and it is a very modern browser and supports all the basic W3C standards very well. So I trust it.

So there you go: just test IE 6.0, IE 8.0, Firefox 3.6, and Chrome 4.1 and you are good to go.


IE6 and IE8 at the same time? How do I install them at the same time?

Simply download the Multiple IE application from TredoSoft and it allows you to test IE3, IE4, IE5, IE6, in addition to your existing IE8 browser (if you have IE7 simply upgrade to IE8). Once you install go to Start -> All Programs -> MultipleIEs -> Internet Explorer 6.0.


IE 6.0 is so old school, can I skip it?

NO YOU CANNOT. I can't stress enough that you MUST test IE6 because it is still widely used, and it is VERY problematic. One of its most serious bugs is that you cannot use mouse to select text of some webpage. Anyway IE6 is still quite modern and supports basic standards decently. You can use Prototype, JQuery, etc. and it'll work in IE6 sometimes with tweaks. Once you make sure your website renders fine in IE6 you can almost rest assured that it renders fine in the remaining major browsers If somehow you cannot install Internet Explorer 6 on your Windows refer to How to install IE6 so you can test your website to solve this issue!


Any reference you recommend?

Yes I recommend QuirksMode.org as it lists all the browser quirks in nice graphs. You can find out which CSS and DOM aspect is supported by which browser and which version. It's EXTREMELY useful.

Testing Out Lucid Lynx

If you head over to http://cdimage.ubuntu.com/daily-live/current/ you can get the most recent build of Lucid Lynx. I went ahead and created a Virtual Box VM since I didn't have time to reformat my hard drive. Seems pretty stable to me, but go ahead and try it out for yourselves.