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Unix Architecture

Priya Pedamkar
Article byPriya Pedamkar

Updated July 1, 2023

Unix Architecture

 

 

Introduction to Unix Architecture

The architecture of Unix is divided into kernel, hardware, shell, files and directories in which the kernel manages the connections related to hardware, applications, and commands. While the second layer is hardware, and the third layer, called a shell, is the bridge between the user, commands executed by the user, and the commands in Unix that are already predefined the last layer is files and directories, which are called Unix programs mostly and can be considered as commands in Unix.

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Unix Definition

UNIX is commonly referred to as an operating system that is utilized in both workstations and servers. This is important for the development of the internet and the reconfiguration of computer systems. Ken Thompson, Dennis Ritchie, and other people working at AT&T laboratories developed Unix Unix. Mainly programmers developed this software to help develop software rather than non-programmers. However, now everyone uses it due to its simplicity. The kernel design facilitates multitasking and time-sharing configurations, allowing multiple individuals to access the system simultaneously.

Unix Working

UNIX operated systems are classified into various sub context let us know about them below-

  1. The first step is the Plain Text for data storage.
  2. This consists of the hierarchical file system.
  3. Considering treating devices and interprocess communications as a file.
  4. The fourth part involves utilizing a multitude of software tools, which can be classified as small programs connected through an interpreter using pipes.

Unix Application Programming Interface

Many operating systems have a simple view of how applications behave depending on their use. The operating system reads data from the disk, terminal, printer, or tape, and its application processes the data. Afterwards, the application written in the operating system produces the required output on the disk, terminal, printer, or tape. Generally, operating systems are inbuilt with well-implemented facilities to support such kinds of applications.

As the applications’ demand increases, the need for more sophisticated features such as network access, inter-process communication, and multitasking also increases. These features lack documentation and may not be easily understandable. The main thing is these are callable only from assembly-level language. The kind of program written with these features is tough to handle and maintain.

The Unix os is written in C language the “input-processing-output” application can be run easily without writing assembly language.

Unix Architecture

The architecture of UNIX is divided into four main layers-

  1. Kernel
  2. Hardware
  3. Shell
  4. Files and directories

The first layer of the kernel manages all the hardware connections while it associates all the applications and commands. Hardware is the second layer. The third layer, known as the shell, acts as the bridge between the user, user commands, and predefined UNIX commands. Last but not least, files and directories can be considered UNIX commands, which are typically UNIX programs. The final layer is the user. This means the whole operating system is visible from the shell itself to the user.

Let us know about each of them in detail:

1. Kernel

Amongst the four layer, ‘s kernel is the most powerful one. The kernel contains mainly utilities along with the master control program. Kernel programs can start or stop a program and even handle the file system. It also suggests which program to select when two resources try to access the device simultaneously for the same resource. As the kernel has special access to the OS, this leads to space division between user-space and kernel space.

The kernel structure is designed to support the primary requirements of UNIX. Which are divided into two categories and listed below

  1. Process management.
  2. File management.
  • Process Management

The resource allocation in CPU, memory, and services are a few things that will be handled under process management.

  • File Management

File management deals with managing all the data in files needed by the process while communicating with devices and regulating data transmission.

The main operations done by the kernel are

  1. The kernel ensures that user-given programs are executed in a timely manner.
  2. Plays a role in memory allocation.
  3. Manages the swapping between memory and disk.
  4. Transports data between peripherals.
  5. The kernel also requests service from the process.

The kernel is commonly referred to as the heart of the UNIX system because of this particular reason. We can define the kernel as a small program containing sufficient data structures to pass arguments, receive results from a call, and process them within the calling process.

2. Hardware

We can define hardware as the system components that are visible and tangible, such as keyboards, monitors, etc. Hardware also encompasses speakers, clocks, and devices in the OS architecture.

3. Shell

We can define the shell as a software program that acts as a communication bridge between the kernel and the user. When the user gives the commands, the shell reads the commands, understands them, and then sends a request to execute the program. When executing a program, it then sends a request to display the program on-screen to the user. The shell is also commonly referred to as a command interpreter. As told above, the shell calls the kernel there are all most 100 in build calls.

Various tasks that the shell ask the kernel to do are

  1. File opening.
  2. File writing.
  3. Executing programs.
  4. Obtaining detailed information about the program.
  5. Termination of the process.
  6. Getting information about time and date.

4. Unix Files And Directories

This includes user-written and shell programs as well as libraries of UNIX

Directories

Directories in Unix have names, path, files, and folders. Rules for both files and folders are the same. They reside in a hierarchical tree structure with an upside-down arrangement. The main working flow of directories is as follows.

  • Displays home directories.
  • Copies files to other directories.
  • Renaming directories.
  • Deleting directories.

Files

These are the files that contain data, text, and program instructions. The main workflow of files is

  • Store user information like an image drawn or some content written.
  • Mostly located under a directory.
  • It does not allow/store the data of other files.

Conclusion -Unix Architecture

In this, we have discussed the Unix system’s most important topics and learned the basics of the operating system. The kernel makes Unix the most secure operating system than Windows. Excluding ease of operation for the user, which is a Windows operating system, Unix is most preferred over Windows, and its users are increasing daily. Many software companies, from start-ups to Mnc’s, use Unix operating systems.

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