Windows was a choice for operating systems for a long time for most users of personal computers. The main reason for its popularity is its user interface and software compatibility. Before the details of the Windows operating system, we will see some of the other operating systems. Outside of Windows, other operating systems to the most popular are the popular Mac and Linux distributions. Macintosh, Apple has been driven by an operating system of computers manufactured by Apple. This is not compatible with other materials, except those from Apple. The distribution of other more common is the Linux distribution. Linux is an open source operating system that is available for use under different distributions. Some of the popular Linux distributions, Ubuntu, Red Hat Linux, OpenSUSE, etc. One of the advantages of Linux over other OS, that it is completely free and, depending on the needs of users, adding the code be amended source.

Now that we have a short overview of the different operating systems, we will also address the use and the benefits of such OS. The Windows operating system was an option for many computer users for years. Although many versions of Windows has published some of the most popular of them is Windows XP. XP is based on the Windows NT family of operating systems. With an interface friendly and more compatible software, it has very popular operating system for a long period. There are many advantages and disadvantages of using Windows OS.
» Read more: Choosing Your Operating System – Windows Or Linux

Some people are curious with a different operating system. You may have heard of Linux, but are not sure you actually install it on your computer to just take a look how it worked. There is a way to try Linux without installing anything. This is done by a so-called Live CD.

The first thing you should do get a Live CD for Linux. Some stores have live CD that you buy a very cheap price. You can access sites such as Ubuntu and load the CD and burn it onto a blank CD of your choice. You can get a free CD by many Linux distributions. You can also buy a magazine with a Linux CD to get into them, with an operating system on them.
» Read more: How to Try Linux Without Installing Anything to Your Computer

Linux Synchronization
We need mechanisms for synchronization when two or more threads simultaneously access a shared resource. By using synchronization mechanisms of the kernel only allows one thread to wait during the execution of other threads.

Competition in the processor systems
One might think that, how many threads can run simultaneously, if a single processor. In a single processor system, even though multiple threads can not operate simultaneously, but one thread can be displaced by an interrupt, or it can be descheduled run at a different thread on the CPU. Preemption may raise competition concerns even data loss, etc. Result barring an interruption masking is a simple technique used on single processor systems to solve problems associated with competition. If a global variable is both an interrupt handler and a kernel thread, the interrupts are masked, the wire during the read shared / update the shared variable.

Competition on SMP systems
On an SMP system are two or more processors on a single shared main memory. Several threads can run simultaneously on different processors, and can access data simultaneously on the main memory. Here is masking interrupts on a single processor or all processors solve the problem is not that we are still running talks on other processors. We need more complex mechanisms by which we will discuss later.

Problems with simultaneous access to shared resources
It is very important to understand the problems or side effects caused by simultaneous access to a resource from multiple threads. Let us understand this with a simple example.

Suppose there is a global variable called “state” (8 bits wide). Consider two threads where one thread wants to define a number of bits, while thread 2 wants the number two state bits of the shared variable. If a bit is already set, they must stay together.
» Read more: Linux Kernel Synchronization