Functions of the Operating System and how it Works
The OS plays a vital role when it comes to starting and shutting down the computer which is also known as booting. Six steps take place when a computer is booting: The first step begins as soon as the computer is turned on, the electrical signal reaches to the components in the system unit through the power supply. During the second step, the processor chip is reset due to the electric signal and then it locates the ROM that contains the basic input/output system (BIOS), which is a firmware that contains the startup instructions of the computer. Next, the BIOS launches a series of tests to ensure hardware are working and connected properly, known as the power on self-test (POST), usually when the POST launches, the LED lights of the devices flicker, at times there will be messages displaying on the screen. The forth step takes place when the POST compares the result with the complementary metal-oxide-semiconductor (CMOS) chip data. CMOS uses battery power to preserve the information, data, and memory when the computer shut down. Besides that, it detects new devices and identifies them when these devices are connected to the computer. The “beep” sound usually results when the CMOS detects which later followed by the error messages. The fifth step proceeds when the POST completes without any interference where the BIOS will locate the OS files also known as the system files from any source of drive. The sixth steps occurs when the system file is located, which is then loaded into the RAM from its storage along the kernel of the OS. The system file then launches, and finally, the OS which was stored in memory takes control of the whole computer system. During the final step, the OS loads the information setting. Certain OS may request for user ID and password. After the OS loads, it displays the desktop screen and it starts up background processes.
The second function of the OS is by providing a user interface. The two types of user interface are the graphical user interface (GUI) and the command-line interface. The GUI basically provides user with an easy way to perform a command or task by having the menus with buttons or other pictures to allow user to click it with ease. Instead of having simple buttons to click on, advance users work with command-line interface to configure, manage and troubleshoot devices and other software. The command-line interface works only with commands by using the keyboard. To perform such command, one must type in the commands accurately with the exact spellings and punctuations.
OS also manages programs. It depends on certain OS, some OS can only run one program at a time, while some can run up to thousands of programs at the same time with one or multiple users. There are the single user/single tasking OS, single user/multitasking OS, multiuser OS, and the multiprocessing OS. When one multitasks, the program that is actively used by the user is said to be in the foreground, while the other programs are known to be in the background.
The OS’s fourth function is memory management. The OS does so by transferring the data and program instructions from the RAM to the hard disk when they are not needed at the moment because at times there is only limited space for the RAM when it has to perform other functions, when the same data and program instructions is needed again, the OS then transfer them from the hard disk to the RAM.
The fifth function of the OS is coordinating tasks. As the phrase implies, the OS determines the order of the tasks which are processed. User can adjust or set the priority of certain tasks, in which result the other tasks to queue up until the preceding task is performed.
Every hardware has a driver which acts like a manual. The sixth function in this case, allows the computer to identify and install it without having the computer to thoroughly “learn” all the details of the hardware. With the Plug and Play technology today, the OS can automatically configure the new devices as the devices are installed on the computer.
The OS is also very important by providing a consistent way for software to deal with hardware without having the computer to thoroughly learn all the details of hardware. The OS interacts with the hardware via drivers. An easy example would be installing a printer to many computers.
The seventh function allows user to easily connect to the internet instead of having to configure the tedious broadband service. OS can automatically configure the internet connection.
The OS also function as a performance monitor, which in this case identify and reports information about the software or the devices of the computer.
Without the OS, the computer is said to be useless and unable to perform. The example of a personal computer OS are: Windows7, Mac OS X, Linux, Amigo