Part 1 Operating system basics

Exercises to the subject:

I. Study the text title given below. What do you think it means?

II. Read the text to check your answer and to find the answers to these questions:

1. What difference is between applications software and operating systems?

2. Why is the supervisor program the most important operating system program?

3. What is the difference between resident and nonresident programs?

4. What are the main functions of the operating system?

Operating Systems: Hidden Software

When a brand new computer comes off the factory assembly line, it can do nothing. The hardware needs software to make it work. Are we talking about applications software such word-processing or spreadsheets? Partly. But an applications software package doesn’t communicate with the hardware directly. Between the applications software and the hardware is the software interface – an operating system. An operating system is a set of programs that lies between the applications software and the hardware.

The most important program in the operating system, the program that manages the operating system, is the supervisor program, most of which remains in memory and is thus referred to as resident. The supervisor controls the entire operating system and loads into memory other operating system programs (call nonresident) from disk storage only as needed.

An operating system has three main functions (1) manage the computer’s resources such as the central processing unit, memory, disk drives, and printers (hardware); (2) establish a user interface; and (3) execute and provide services for applications software. When several jobs reside in the computer simultaneously and share resources (multitasking), the OS allocates fixed amounts of CPU time and memory in turn or allows one job to read data while another writes to a printer and still another performs computations. Through a process called time-sharing, a large computer can handle interaction with hundreds of users simultaneously, giving each the perception of being the sole user. Keep in mind, however, that much of the work of an operating system is hidden from the user. In particular, the first listed function, managing the computer’s resources, is taken care of without the user being aware of the details.

Furthermore, all input and output operations, although invoked by an applications program, are actually carried out by the operating system.

Modern computer operating systems are becoming increasingly machine-independent, capable of running on any hardware platform; a widely used platform-independent operating system in use today on mainframe computers is UNIX. Most personal computers run on Microsoft’s Windows operating system, which grew out of and eventually replaced MS-DOS, or MacOS.

III. Complete the following sentences.

1. An operating system is software that …

2. An operating system manages …

3. To store information in files on the disk the operating system performs such tasks as …

4. The function of the device driver program is …

5. Operating system that runs one application program or task at a time is called…

6. More than one application program or task can be active at time due to …

7. The operating system can provide such network services as …

8. The operating system uses multimedia to accomplish …