Operating Systems Architecture

Operating Systems Architecture

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General Architecture of a Operating System

Learning objective: Explain the general architecture of a operating system

kernel
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An operating system is a program that acts as an interface between a user of a computer and the computer resources. The purpose of an operating system is to provide an environment in which a user may execute programs.

Hardware

The hardware consists of the memory, CPU, arithmetic-logic unit, various bulk storage devices, I/O, peripheral devices and other physical devices.

Kernel

In computing, the kernel is the central component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software components). Usually as a basic component of an operating system, a kernel can provide the lowest-level abstraction layer for the resources (especially processors and I/O devices) that application software must control to perform its function. It typically makes these facilities available to application processes through inter-process communication mechanisms and system calls.

Shell

A shell is a piece of software that provides an interface for users to an operating system which provides access to the services of a kernel. The name shell originates from shells being an outer layer of interface between the user and the innards of the operating system (the kernel). [Wikipedia]

Operating system shells generally fall into one of two categories: command-line and graphical. Command-line shells provide a command-line interface (CLI) to the operating system, while graphical shells provide a graphical user interface (GUI). In either category the primary purpose of the shell is to invoke or "launch" another program; however, shells frequently have additional capabilities such as viewing the contents of directories.


✏ Self Quiz!

Select the best response(s) for each question/statement. Use this opportunity to test *your* knowledge and not just move on...

1) The kernel's role is to:
Communicates with the user
Manages the hardware
Communicates with the user AND manages the hardware

2) The shell's role is to:
Communicates with the user
Manages applications
Manages communication ports

.


Thinking: Why make the shell separate from the kernel?

Key terms: CLI, GUI, hardware, kernel, shell

Resources:
To maximize your learning, please visit these Web sites and review their content to help reinforce the concepts presented in this section.

Quick links:
Chapter 1 Introduction into Operating system @ UNESCO (www.netnam.vn/unescocourse/os/11.htm)
Kernel @ Wikipedia
Shell @ Wikipedia

Embedded Resources

Notes on navigation: Click inside the frame to navigate the embedded Web page. - Click outside the frame to navigate this page to scroll up/down between the embedded Web pages. - Click on the frame title to open that page in a new tab in most browsers. - Click on the the "Reload page" link to reload the original page for that frame.

Chapter 1 Introduction into Operating system @ UNESCO (www.netnam.vn/unescocourse/os/11.htm) | Reload page | If frame is empty, click on the link to view the page in a new tab or window

Kernel @ Wikipedia | Reload page | If frame is empty, click on the link to view the page in a new tab or window

Shell @ Wikipedia | Reload page | If frame is empty, click on the link to view the page in a new tab or window

| Reload page | If frame is empty, click on the link to view the page in a new tab or window

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