What is an operating system?

The operating system can be evaluated from different angles:
  • An operating system is a number of files, which are read from the hard disk at the end of of the PC start-up routine.
  • An operating system is a program layer. It connects to the the PC hardware, to facilitate optimal execution of the user programs.

The first definition does not say much. Let us start with the second: The operating systems links software and hardware together. It has to enable user programs, like Works, Office, etc., to function with all possible hardware configurations. You can imagine the relationship between hardware and user
programs thus:

  • Hardware is clumsy and dissimilar. There are untold variations of PC's. They can have one or another type hard disk, CPU, video card, etc. All of these various PC configurations behave each in their own way.
  • The use programs are 100% similar. They are off the shelf products, which expect the PC to respond in a certain manner.
How do we make these two layers work together? Can we eliminate out the differences in the PC hardware, so a standard product like Works just functions? Yes we can. We read in an operating system- a system layer, which smoothes out and standardizes the hardware:

You should understand the operating system as a necessary layer, which smoothes out bumps and pot holes in your PC's hardware. This will give the user programs a stable, even work platform.

The operating system recognizes hardware

The PC's hardware represents resources relative to the user program.
Think of your word processing program: You want to print your text. The program issues a print order, expecting that the document will be printed as designed. The word processing program dispatches data according to your commands. How they are translated to signals understood by your printer - that is not the word processing programs problem. The printer is a resource relative to the word processing program. The connections to these resources is via the operating system. This holds true for all the resources, which are included in the PC hardware:

As you can see, the operating system has a very central function in the PC. So with that placement, it must be able to recognize all forms and types of hardware. There is no point in connecting a new mouse, if it does not work! Then what makes it work - the operating system. The system must recognize your mouse!