Why does my computer need an OS?

Hello Again! :) 

Hey, how's it going? Do you want to know something amazing? Do you know that right now you're using your OS? Do you even know what OS means? No? Really? Well if you don't let me tell you, (if you do then let' just review it).

OS stands for Operating System. And you may ask yourself what an operating system is, well an OS is a software that enables the computer hardware to communicate and operate with the computer software. Without a computer OS a computer and software programs would be useless. 

"The OS function is to organize and control hardware and software so that the device it lives in behaves in a flexible but predictable way." just like HowStuffWorks affirms. 

Do all computer have OS? Nope, not all computers have OS. There are some electronic devices that don't need an OS to work, for example your calculator, because it only has one set of tasks to perform, very straightforward input to expect (a numbered keypad and a few pre-set buttons) and simple, never-changing hardware to control. "For a computer like this, an operating system would be unnecessary baggage, driving up the development and manufacturing costs significantly and adding complexity where none is required. Instead, the computer in a microwave oven simply runs a single hard-wired program all the time." as HowStuffWorks explains.

Now let me ask you, do you know the 3 most common OS?

Well, the three most common OS are:

Apple

Linux

And Microsoft

 How does the OS help my computer work? What types of OS exist?

The OS help the computer by making 2 basic things.

It manages the hardware and software resources of the system.

It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware

There are 4 types of OS

1. Real-time operating system (RTOS) - Real-time operating systems are used to control machinery, scientific instruments and industrial systems. A very important part of an RTOS is managing the resources of the computer so that a particular operation executes in precisely the same amount of time, every time it occurs.
2. Single-user, single task - This OS is designed to manage the computer so that one user can effectively do one thing at a time.
3. Single-user, multi-tasking - This is the type of OS most people use on their desktop and laptop computers today. There are OS that will let a single user have several programs in operation at the same time.
4. Multi-user - Allows many different users to take advantage of the computer's resources simultaneously. The OS must make sure that the requirements of the various users are balanced, and that each of the programs they are using has sufficient and separate resources so that a problem with one user doesn't affect the entire community of users.

Based on the document in HowStuffWorks

http://computer.howstuffworks.com/operating-system10.htm/printable

Is data really deleted?

I just read this article about how things never get eliminated completely of your hard disk unless you destroy de hard drive. 

The article talked mostly about this experiment about some students made of buying computers and searching for private SUPER IMPORTANT information (such as credit cards, fotos, and important passwords and data) and got like 74% of that information back, and only 9% of people had correctly deleted everything on their computer.

I talked to my mother about this and she wasn't completely shocked because she says that one of her friends is really good with technology and that she's always telling those things to her friends. But when I talked to my father about it he REALLY was shocked because he truly didn't know that the things he erased weren't completely gone, and because he got one of his computer stolen he was super nervous about the information that he had that. 

Now I tell you what would you do if all the information that you've ever written, seen or played was founded by someone else?