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Unformatted text preview: controlled? Chapter 14
In the last few chapters we have dealt with the planning, coding, operation, and
maintenance of software systems. In the next few chapters, we will have a look at
some of the commonly used software in today's computer systems. In this chapter,
you will learn about a very important and special type of software that falls under
the category of system software. This system software is known as operating
system. In the next chapter you will learn about some commonly used application
An operating system is an important part of almost every computer system. The
goal of this chapter is to introduce concepts related to operating systems and to
show how this particular system software helps in the overall operation and usage
of a computer system.
WHAT IS AN OPERATING SYSTEM?
An operating system (often referred to as OS) is an integrated set of programs that
controls the resources (the CPU, memory, I/O devices, etc.) of a computer system
and provides its users with an interface or virtual machine that is more convenient
to use than the bare machine. According to this definition, the two primary
objectives ol an operating system are as follows:
1. Making a computer system convenient to use. A computer system consists of
one or more processors, main memory and many types of I/O devices such as
disks, tapes, terminals, network interfaces, etc. Writing programs for using these
hardware resources correctly and efficiently is an extremely difficult job, requiring
in-depth knowledge of the functioning of the resources. Hence to make computer
systems usable by a large number of users, it became clear several years ago that
some way is required to shield programmers from the complexity of the hardware
resources. The gradually evolved solution to handle this problem is to put a layer
of software on top of the bare hardware, to manage all parts of the system, and
present the user with an interface or virtual machine that is easier to program and
use. This layer of software is the operating syste...
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- Spring '14