PART- A

Q.No Questions Marks

Define Operating System.

1 An operating system is a program that acts as an interface between the user and the 2
computer hardware and controls the execution of all kinds of programs.
List out functions of Operating Systems .
 Memory Management
2  Processor Management 2
 Device Management
 File Management
Write down the advantage of Operating Systems.
 It is helpful to monitor and regulate resources.

3  It is used to create interaction between the users and the computer application or 2
hardware.

The performance of the computer system is based on the CPU.

Difference between Application Software and System Software.
System Software Application Software
 This acts as an interface between  This is designed directly from the
the system and the applications user perspective

 It is the platform that allows the  These are independent applications

4 various application software to which can be download and 2
run on the system installed in the system

 These are responsible for the  They have minimum involvement

working of the system in the processing and functioning of
the computer device

List out the Popular Operating Systems.

5 The popular Operating Systems include Linux Operating System, Windows Operating System, 2
VMS, OS/400, AIX, z/OS, etc.

PART- B
Q.No Questions Mar
ks
1. What are the functions of Operating Systems? 16

Functions of Operating Systems:

The main operation performed by operating system is to carries out is the allocation of
resources and services, such as allocation of the following −
 Memory
 Devices
 Processors
  Information
The operating system includes programs that are helpful to manage these resources, such as
a traffic controller, a scheduler, memory management module, I/O programs, and a file
system.

Functions of Operating Systems Diagram:

Security
The operating system uses a password protection to protect user data it also prevents
unauthorized access to programs and user data, but for external functionality we need to
install malware software to protect the system.
Control over system performance
 The operating system monitors overall system setup to help in improving the
performance and it also records the response time between service requests and
system response so that it has a complete view of the system.
 This can help improve performance by providing important information that is
needed at the time of troubleshooting problems.
Job Accounting
Operating systems always keep track of time and resources that are used by various tasks
and users, this information can be used to track resource usage for a particular user or a
group of users.
Error detecting aids
Operating systems constantly monitor the system which helps us to detect errors and also
avoid the malfunctioning of computer systems.
Coordination between other software and users
Operating systems help in coordinate and assign interpreters, compilers, assemblers, and
other software to the various users of the computer systems.
Memory Management
 The operating system controls the primary memory or main memory.
 Primary memory is a large array of bytes or words where each byte or word is
assigned a certain address.
 It is a fast storage, and it can be accessed directly by the CPU which is present inside
the system. If a program wants to be executed, it should be first loaded in the main
memory.
The following activities are performed by operating system for memory management −
 It keeps track of primary memory.
 Memory addresses that have already been allocated and the memory addresses of the
memory that has not yet been used.
 In multiprogramming, the OS decides for how long the process must stay and the
order in which processes are granted access to memory.
 It allocates the memory to a process when the process requests it and deallocates the
memory when the process has terminated.
Processor Management
 The OS manages the order in which processes have access to the processor, and how
much processing time that each process must stay in the multiprogramming
environment.
 This is called process scheduling.

The following activities are performed by operating system for processor management −
 Keeps track of the status of processes.
 The program to track the status is known as traffic controller.
 It allocates the CPU and deallocates the processor when it is not required.
Device Management
An OS manages device communication through respective drivers.
The following activities are performed by the operating system for device management.
 Keeping track of all devices connected to the system.
 The OS designates a program that is responsible for every device which is called the
Input/output controller.
 It decides which process gets access to which device and for how long. It then
allocates the devices in an effective and efficient way and de-allocates devices when
they are not required.
File Management
A file system is arranged into directories for efficient navigation and usage. These
directories contain other directories and other files.
The following activities are performed by operating system for file management activities −
 It keeps track of where information is stored, user access settings and status of every
file and more.These facilities are called the file system.