Unit 2

Question 1

Whats a system software

Answer 1

Refers to the operating system and all utility programs that manage computer resources at a low level
it includes compilers,loaders,linkers and debuggers

Question 2

What are Application Programs?

Answer 2

A program or group of programs designed for end users. Eg: Word processing,Graphics

Question 3

What is an Operating system?

Answer 3

An operating system is an interface between the user and hardware of the computer system and controls the execution of all kinds of programs

it is a system software which may be viewed as an organized collection of software consisting of procedures for operating a computer and providing an environment for execution of programs.

Question 4

Goals of an operating system are?

Answer 4

To make the computer system convenient to use

to use the computer hardware in an efficient manner

Question 5

Whats the purpose of an operating system?

Answer 5

The purpose of an OS is to provide an environment in which the user may execute programs

Question 6

Whats User Interface

Answer 6

a set of commands or menus through which user communicates with the programs

Question 7

What are the types of Interfaces?

Answer 7

Command driven

Question 8

What are the types of Interfaces?

Answer 8

Command driven
menu driven
GUI

Question 9

What are the types of Interfaces?

Answer 9

Command driven
Menu driven
GUI

Question 10

What are the ways to interact with the OS?!

Answer 10

OS Calls
OS System commands

Question 11

What are OS calls?

Answer 11

Invokes services of the operating system by means of run time system calls

these are usually embedded in and activated during execution of programs

Question 12

What are OS Commands

Answer 12

These are used to obtain services of the OS by means of commands typed at the terminal or embedded in a batch job

Question 13

What are the Functions of the Operating System?

Answer 13

Memory Management
Process Management
Device Management
Information Management
Protection
Error Handling

Question 14

Whats Memory Management?

Answer 14

The OS keeps track of the memory,what parts are in use and by whom?

Question 15

what process management?

Answer 15

the OS keeps track of processors and the status if processes. It decides who will have a chance to use the processor

Question 16

Whats Device management?

Answer 16

The OS keeps track of the devices,channels,control units and decides what is an efficient way to allocate the device.

Question 17

Whats information Management?

Answer 17

OS keeps track of the information,its location,use,status etc and decide who gets use of the resources, enforce protection requirements.

Question 18

Whats information Management?

Answer 18

OS keeps track of the information,its location,use,status etc and decide who gets use of the resources, enforce protection requirements.

Question 19

Whats Protection?

Answer 19

An OS is to protect the user from unauthorized access of his files or data. And also it should protect itself from users.

Question 20

Whats Error Handling?

Answer 20

An OS must respond to errors by taking the appropriate actions?

Question 21

What are the Dual mode Operations in OS?

Answer 21

User mode and Kernel Mode

Question 22

Whats user Mode

Answer 22

When the computer system is run by user application like creating a text documents or suing any application program then the system is in user mode. When the user application request for a services from the operating system or an interrupt occurs or system call, then there will be a transition from user to kernel mode to fulfill the requests

Question 23

What is necessary to switch from kernel mode to user mode!?

Answer 23

To switch from kernel mode to user mode, the mode bit should be 1

Question 24

Whats Kernel Mode?

Answer 24

When the system boots, hardware starts in kernel mode and when the operating system is loaded, it starts user application in user mode. TO provide protection to the hardware we have privileged instruction which execute only in kernel mode. IF the user attempts to run privileged instructions in user mode then it will treat instructions as illegal and traps to OS.

Question 25

What are some of the privileged instructions?

Answer 25

Handling interrupts
To switch from user mode to kernel mode
Input-output management

Question 26

To switch from user mode to kernel mode whats necessary?

Answer 26

To switch from user mode to kernel mode Mode bit should be 0

Question 27

What are the Types of OS?!

Answer 27

Batch OS
Multiprogramming OS
Distributed OS
Network OS

Question 28

Explain Batch OS

Answer 28

Batch processing generally requires the program,data and appropriate system commands to be submitted together in the form of a job
Batch OS usually allow little or no interaction between users and executing programs
Scheduling in batch systems is very simple and are processed in the order of submission
memory management in batch system is also very simple
Memory is divided into 2 areas: Permanently occupied by the resident portion of the OS; Is used to load transient programs for execution
Eg: Payroll,Forecasting,Satistical analysis and large scientific number crunching programs

Question 29

Whats Multiprogramming OS?

Answer 29

Multiprogramming is essentially multiplexing of system resources such as processor, memory and I/O devices among a number of active programs
Multiprogramming is used as a technique to enhance the throughout efficiency
overlapping interleaving computing of different jobs
more than one job is ready at the same time
these are characterized by a multitude of simultaneously active programs that are competing for system resources, such as processor, memory and I/O devices.

Question 30

What are Different types of Multiprogramming OS?

Answer 30

Multitasking OS
Multiprocessing OS
Multiuser OS