Operating System – Function or role of the Kernel and shell Long Questions Answers

Here in this section of Operating System Long Questions and Answers,We have listed out some of the important Long Questions with Answers on Kernel and shell which will help students to answer it correctly in their University Written Exam.

Lists of Long Descriptive type Questions that may be asked in Written Exams.

• (1) Explain the role or function of the kernel.
• (2) Explain in brief roles/ functions of shell..

Question-1 Explain the role or function of the kernel.

• Each process asks for the system resources like computing power, memory network connectivity etc. The kernel is the bulk of the executable code in charge of handling such request.
• The kernel is the main component of most computer operating systems. It is a bridge between applications and the actual data processing done at the hardware level.

The following are the major role of the kernel

Resource allocation

• The kernel’s primary function is to manage the computer’s resources and allow other programs to run and use these resources. These resources are- CPU, Memory and I/O devices.

Process Management

• The kernel is in charge of creating, destroying and handling the input output of the process.
• Communications amongst the different processes is the responsibility of the kernel.

Memory Management

• The memory is the major resource of the computer and the policy used to deal with it is a critical.
• The kernel builds a virtual address space for all the process on the top of the resource. The different parts of the kernel interact with the memory management subsystem by using the function calls.

File System

• The kernel builds the structured file system on the top of the unstructured hardware.
• Kernel also supports the multiple file system types that is different way of managing the data.

Device Control

• Every system maps into the physical device.
• All the device control operations are performed by the code that is specific to the device being addressed. This code is called device driver.

Networking

• It will be managed by the operating system and also control the program execution according to the network activity.
• Routing and address resolution issues are also handled by the kernel.

Inter – Process Communication

• Kernel provides methods for Synchronization and Communication between processes called Inter- Process Communication (IPC).
• There are various approaches of IPC say, semaphore, shared memory, message queue, pipe (or named fifo), etc.

Security or Protection Management

• Kernel also provides protection from faults (error control) and from malicious behaviors (Security).
• One approach toward this can be Language based protection system, in which the kernel will only allow code to execute which has been produced by a trusted language compiler

Question-2 Explain in brief roles/ functions of shell.

UNIX shell act as a command interpreter.

• It gathers input from user and executes programs based on that input, when a program finishes executing; it displays that program’s output.
• It is primary interface between a user sitting at his terminal and operating system,unless the user is not using a graphical interface.
• A shell is an environment in which user can run our commands, programs, and shell scripts.
• There can various kinds of shells such as sh (bourne shell), csh (C shell), ksh (korn shell) and bash.
• When any user logs in, a shell is started.
• The shell has the terminal as standard input and standard output.
• It starts out by typing the prompt, a character such as $, which tells user that shell is waiting to accept command.
• For example if user types date command,
  • $ date
• Tue Feb 26 06:01:19 IST 2019
• The shell creates a child process and runs date program as child.
• While the child process is running, the shell waits for it to terminate.
• When child finishes, the shell types the prompt again and tries to read the next input line.
• Shell is work as interface, command interpreter and programming language.
• Shell – As interface
• Shell is interface between user and computer.
• User can directly interact with shell.
• Shell provide command prompt to user to execute commands.
• Shell – As command interpreter
• It read command enter by user on prompt.
• It Interpret the command, so kernel can understand it easily.
• Shell – As programming language
• Shell is also work as programming language.
• It provides all features of programming language like variables, control structures and loop structures.