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How Does an Operating System Work?

Arun Prabhu
With the introduction of Operating Systems in things as small and as useful as cell phones, it's essential to know a little about what they are. The knowledge of an operating systems function goes a long way when you use it, especially for troubleshooting and programming.
Imagine this, the human body has muscles to move, a heart to pump blood into them, an immune system to fight off viruses, eyes to see and the skin to touch, etc. So the body is pretty much set to do its job, right? Of course not, you'll need a brain to function too. 
The brain is the organ that gives the body orders, accepts the inputs from the body and assesses them, doing what's needed to get the job done and survive. Now, an interesting point here is that simple reflexes are controlled by the spinal cord. So there are some functions that don't need the brain, in a figurative sort of way.
In the same way, there are several simple technological functions that do not require too much programming. Just a little hard-wired coding and you're set. For example, an elevator or a refrigerator or a microwave. There are only a few repetitive functions that these things need to do. 
Now, consider a multitude of such simple functions, coming together to perform a larger function. Now, you'll need another function/program to run these smaller functions. That's what an Operating System is. 
You may not know the innermost simple ones, but you know what's happening on your screen. It's the same with a mechanical watch, you don't know the parts, but you know the time it tells. The difference is, a lot more depends on the operating system, which brings out the need to know more about them.

What Makes an OS?

There are some requirements that a system needs to qualify as an OS (apart from having "Windows" or "Mac" in their names):
✦ The system needs to be able to carry out multiple functions (not necessarily at the same time) to provide the most relevant output to the user as fast as possible.
✦ The system needs to be interactive with the user, asking and providing with whatever is required at each step.

✦ The system effectively links the application software to the computer's physical hardware.
Simply put, a computer is useless if it does not have an OS installed. It is the program that runs all programs. You may think you control what goes on the monitor, but it's actually the OS in there, toiling away to make whatever you told it to.
You'll find an OS in all desktops, Apple Macs, smartphones, special task-oriented operating systems used for control systems. The different types of OS available today are wide, so you get to choose the one you're most comfortable.

What Makes an Operating System Tick?

The OS needs to apply itself to a lot of areas to be able to run the computer effectively.

Device Management

On the outermost level, an OS is like an interpreter-plus-goodwill ambassador for two politicians who speak different languages. The interpreter needs to deliver the dialogs between the two in the most accurate way possible, in order to maintain peace between both. So the OS acts the same way for the system hardware and program software.
Neither knows the other or how they work, and the job thus falls to the OS. The OS has to deliver the most relevant and precise data to the hardware from the software and the calculated output back to the software, which is in direct view of the user. This also means managing the version gaps between different applications or hardware.

Memory Management

The OS is also given the important task of resource management. This includes the resources of processor speeds, hardware memory, disk space, etc. It needs to be careful of not letting memory on any side to overlap another, this will cause data loss.

Application/Device Change Management

The OS also needs to be provided with a consistent application interface. This includes multiple computers that possess the same OS.
If you work on something on one computer, the OS needs to make sure that it will work on another computer with the same OS.

User Interface Management

The OS needs to make the user interface (what you see on the screen) as simple and straightforward as possible.
It also needs to take care of the look and feel of the interface for the user to like it. This also includes the effectiveness of the user commands on the applications for them to run as smoothly as possible.

Types of Operating Systems

There are four types of OS that you can use. Choosing one depends on the kind of work you're going to perform on the computer.

Single User, Single Task

This OS is preferred for simple, repetitive tasks and is used in Palm handheld PCs.

Single User, Multi-Task

It is the most common Os you will see around you. It includes Windows and MacOS as well. Useful for performing multiple tasks at the same time, like browsing the Internet while listening to music.

Multi-User

This OS is used by a community of users that apply the OS for similar functions. Running this type of OS requires a lot of resources and maintenance. Unix is one such OS.

Real-Time Operating Systems

An RTOS rarely has any user interface. It is mainly used for managing resources within the computer and does not rely on or stop for the user's input. It works like a fully automated assembly line that does not need manual interactions.
Companies like Microsoft and Apple strive to get the best OS out on the market, giving it a good competitive edge, while you may also go for freeware Operating Systems like Linux. Whatever you choose, the OS needs to be exactly according to what you want it to be.