COMP100 Week 1 Windows and Office Fundamentals Lecture Notes

17. April 2016 School 0

Windows and Office Fundamentals

What is an Operating System?

An operating system is the software environment that supports the execution of user application programs such as Microsoft (MS) Word, MS Excel, and MS PowerPoint. There are many types of operating systems. The most popular ones are Windows, Unix, and MAC OS. There are other operating systems as well for main-frame computers such as IBM’s OS MVS. In this course, we will be using Microsoft Windows as our operating system. There are several versions of Microsoft Windows. Windows XP is very popular as is the newer Windows 7. Both can be used with MS Word 2010, MS Excel 2010, and MS PowerPoint 2010, the three user application programs you will be working with in this course.




You cannot use the Unix operating system to run MS Word, MS Excel, or MS PowerPoint because the Unix operating system and these user application programs would not know how to “talk” to each other. They do not share the same language. To use an analogy, it would be like a customer who didn’t speak Russian, attempting to buy something from a salesperson over the phone who only spoke Russian. The salesperson or the business he represents would be analogous to an operating system and the customer would be the user application program. The business would not be able to provide a basic service because it would not understand the user.

An operating system and its user application programs need to “talk” with each other in a language both can understand. Microsoft Windows and Microsoft user application programs can talk to each other because they share the same protocols. Microsoft protocols are standards that were set up by Microsoft and understood by all software developers so that they can develop software that will be able to communicate with MS Windows. Unix has its own protocols for its applications as does Apple’s MAC operating system. We can use Windows XP or the Windows 7 to run MS Word, MS Excel, or MS PowerPoint because these two operating systems share the same basic protocols and can communicate with them.

So what do operating systems and their user applications talk about? An operating system provides basic user application program needs that will only be executed when a user application program requests it. What are some of those basic needs? User application programs like MS Word need to have their and your personal files managed on disk, they need information to be displayed to and written from a display monitor, and the user applications need to be loaded to and unloaded from computer memory in an efficient way.

Let’s take a closer look at the basic operating system tasks previously mentioned. The first is file management. An operating system needs to perform Input/Output (I/O) procedures that will retrieve data from a disk and write to a disk as well. You will need to retrieve and save your Word document files, for instance, when working in MS Word. Without an operating system, each user application program such as MS Word, would have to provide that basic function in its software. That means the same software written to do that task would have to be written and included in all the different user application programs. There can be hundreds if not thousands of user application programs for an operating system, so forcing each application program to provide the same basic software tasks would be inefficient. You would be always re-inventing the wheel! So what is a better idea? Instead of each user application program providing the same basic tasks, only the operating system would contain the software routines that do those tasks. Then a user application program such as MS Word would only have to request the operating system to do a basic task that it needs to be done. For instance, MS Word would request Windows to read one of your Word document files from disk. The Windows operating system would then execute its “Read” software routine to read your document from disk so that you can see it in Word. It is more efficient to do it that way isn’t it? Basic tasks are written in the operating system software in order to simplify everything. Then those tasks can be shared by all applications. And if any software changes or fixes ever need to be made for that task, then the changes will only be made in one place; in the operating system.




Sometimes a user wants to work with several different user applications or several instances of the same user application program at the same time. Perhaps you have experienced that by now. That concept is called multi-tasking and is a very important basic task that all operating systems provide. Multi-tasking means that an operating system must manage computer memory and do it efficiently so that instances of the same or different user applications programs can run in memory at the same time. The operating system would also have to manage the central processing unit (CPU) efficiently. The CPU executes the software instructions in application programs. In multi-tasking, the operating system would make sure that the CPU is kept very busy and is shared in an equitable way by the application programs that are currently running.

Below is a short list of tasks that operating systems perform for user application programs.

Operating System

An operating system helps the computer perform basic tasks such as:
• Displaying data on the screen
• Printing information
• Tracking files on disks
• Multi-Tasking application programs


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