What is an Operating System?
Ø A
program that acts as an intermediary between a user of a computer and the
computer hardware.
Operating system provided a CLI(command line interface) and GUI to the users.
CLI :this interface provides a command prompt,and the user has to type all the commands to perform certain functions.eg:DOS
GUI:this interface allows manipulation of software by using objects such as windows,pull down menus,mouse pointers and icons.
Ø Operating system goals:
o Execute
user programs and make solving user problems easier.
o Make
the computer system convenient to use.
Ø Use
the computer hardware in an efficient manner.
Ø Computer
system can be divided into four components
o Hardware – provides basic computing
resources
§ CPU,
memory, I/O devices
o Operating system
§ Controls
and coordinates use of hardware among various applications and users
o Application programs –
define the ways in which the system resources are used to solve the computing
problems of the users
§ Word
processors, compilers, web browsers, database systems, video games
o Users
§ People,
machines, other computers
Ø OS is
a resource allocator
o Manages
all resources that include processor,memory-disk space-I/O devices and so on.
o The Operating System provides an
error handling procedure and displays an error notification.
Ø OS is
a control program
·
Controls execution of programs to
prevent errors and improper use of the computer.
Ø Providing
an interface: The operating system
organizes applications so that the users can easily access,use and store them.
·
When an application is
opened,the os tells the application to provide a major part of the interface.
·
If the application program is not
functioning properly,OS takes the control ,stops the application,and displays
an appropriate error message.
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