Operating System

 Operating System
An Operating System (OS) is a set of computer programs that manage the hardware and software resources of a computer. An operating system rationally process electronic devices in response to approved commands. At the foundation of all system software, an operating system performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices,facilitating networking, and managing file system. Most operating system have a command line interpreter as a basic user interface, but they may also provide a graphical user interface (GUI) for ease of operation. The operating system forms a platform for other system software and for application software. Examples of OS are Windows 7, Windows 8, Linux, UNIX, Disk Operating System (DOS) etc.

Services of an Operating System
Process Management : Every program running on a computer, be it background services or applications, is a process. Process management is an operating system's way of dealing with running multi processes that is managing, controlling and monitoring all the running Processes. In many systems there is a background process, such as the System Idel Process in Windows, which will run when no other process is waiting for the CPU.
To see the process management in Windows, right click on Task Bar and select "Task Manager" or press "CTRL=ALT+DEL" from keyboard and click on Task Manager. The Task Manager shows all the running processes, their CPU and Memory Usage. To kill a process, right click on selected process and select "End Process".

Memory Management : An operating system's memory manager coordinates to use of the memory (RAM) by tracking which one is available, which is to be allocated or deallocated and how to move data between them. This activity, usually referred to as virtual memory management, increases the amount of memory available for each process by making the disk storage seem like main memory. The operating system can also write inactive memory pages to secondary storage. This process is called "paging" or "swapping".
The memory allocation and deallocation can also be seen in the Windows Task Manager. To view the swapping/paging of memory, Open System Properties by right clicking on My Computer Icon and Select Properties or simply Press Window key + Pause Break. In the Advanced tab, select settings in the performance category. In  the performance option, select the advance tab, and click on change in the virtual memory section. Now you can see/change the virtual memory of your computer.

Disk and File System : All operating system include support for a variety of file system. Microsoft Windows includes support for FAT12, FAT16, FAT32, and NTFS. FAT stands for File Allocation Table and NTFS stands for New Technology File System. The NTFS file system is the most efficient and reliable of the four Windows system.

Networking : Most current operating system are capable connecting to other computers. This means that one system can appear on a network of the other and share resources such as files, printers, and scanners using either wired or wireless connections.

Graphic User Interface (GUI) : Many OS nowadays provide a graphical interface to its users. That is user do not have to type instructions in the command line to carry out certain operations. They can now use the graphical interface for almost all the processes.

Device Driver : A device driver is a specific type of computer software developed to allow interaction with hardware devices. Typically this constitutes an interface for communicating with the device, through the specific computer bus or communications subsystem that the hardware is connected to, providing commands to and/or receiving data from the device, and on the other end, the requisite interfaces to the operating system and software applications.

Security : Many operating system includes some level of security like granting access to files and resources, avoiding threats and blocking malicious codes. Windows has its own Firewall in it that prevents the system from unauthorized access of files, avoids malicious codes etc.

Computing in Binary Numbers
The primary storage device inside the computer is the transistor that allows your computer to store and process millions of bits of data. A single transistor is capable of holding an electrical charge that is either positive or non-positive (0 or 1 sometimes). Since the objective of the computer is to manipulate data, the electrical states of the transistor (positive and non-positive) are assigned the numerical values of 1 and 0 (zero).

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