The main difference between kernel and shell is that the kernel is the core of the operating system that controls all the tasks of the system while the shell is the interface that allows the users to communicate with the kernel.
Unix is an operating system. It is the interface between the user and the hardware. It performs a variety of tasks including file handling, memory management, controlling hardware devices, process management and many more. There are various versions of Unix: Solaris Unix, HP Unix, AIX, etc. Linux is a flavor of Unix, and it is free and open source. Unix is popular in enterprise level because it supports multiple user environment. Kernel and Shell are two components in Unix architecture. Kernel is the heart of the operating system while Shell is a utility to process user’s requests.
Key Areas Covered
1. What is Kernel
– Definition, Usage
2. What is Shell
– Definition, Usage
3. Difference Between Kernel and Shell
– Comparison of Key Differences
Key Terms
Kernel, Shell, Operating System, Unix
What is Kernel
Kernel is the heart of the operating system. The term kernel often refers to the operating system. The critical code of kernel is stored in a special memory area to protect it from other programs. It is a vital component as it is the basis for the proper functioning of the entire system. Kernel performs a variety of tasks including process management, managing hardware devices and handling interrupts.
Figure 1: Kernel Layout
Furthermore, it performs memory management, file handling and task scheduling. A system call is a request by a process to the kernel. The kernel manages these system calls and other resources.
What is Shell
Shell is the interface between user and kernel. It is a command line interpreter and is the interface between the user and the kernel. The user can enter commands to the shell. Then it interprets the commands to perform the required task. Furthermore, it executes programs and shell scripts. A shell script is a set of commands. The user should follow the standard syntax to write commands to the shell.
Figure 2: Bourne Shell
There are various types of shells. The Bourne shell (sh) is the most popular Unix shell. The default prompt of Bourne shell is $. The Korn shell (ksh) is backward compatible with Bourne shell and includes many features of C shell. Bourne Again Shell (bash) is a free shell replacement for the Bourne shell. The Korn and Bourne Again Shell are supersets of Bourne shell. Furthermore, the C shell (csh) provides few advantages over the Bourne shell. It provides history features and aliasing of commands. The default prompt of the C shell is %.
Difference Between Kernel and Shell
Definition
The kernel is a computer program which acts as the core of the computer’s operating system and has the control over everything in the system. A shell is a computer program which works as the interface to access the services provided by the operating system.
Usage
Kernel is the core of the system that controls all the tasks of the system. Shell is the interface between the kernel and user.
Types
Kernel does not have different types. Shell has different types such as Bourne shell, C shell, Korn Shell, Bourne Again Shell, etc.
Conclusion
The difference between kernel and shell is that the kernel is the core of the operating system that controls all the tasks of the system while the shell is the interface that allows the users to communicate with the kernel. In brief, the shell is the interface that helps the users to access the services provided by the operating system.
Reference:
1. “Unix / Linux Getting Started.” Www.tutorialspoint.com, Tutorials Point, 14 June 2018, Available here.
2. “Unix / Linux What Is Shells?” Www.tutorialspoint.com, Tutorials Point, 14 June 2018, Available here.
3. “Kernel (Operating System).” Wikipedia, Wikimedia Foundation, 10 July 2018, Available here.
Image Courtesy:
1. “Kernel Layout” By Bobbo – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Version 7 UNIX SIMH PDP11 Kernels Shell”By Huihermit – Own work (CC0) via Commons Wikimedia
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