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Introduction to UNIX System

Unix is an Operating System that is truly the base of all Operating Systems like Ubuntu, Solaris, POSIX, etc. It was developed in the 1970s by Ken Thompson, Dennis Ritchie, and others in the AT&T Laboratories. It was originally meant for programmers developing software rather than non-programmers. 

Unix and the C were found by AT&T and distributed to government and academic institutions, which led to both being ported to a wider variety of machine families than any other operating system. The main focus that was brought by the developers in this operating system was the Kernel. Unix was considered to be the heart of the operating System. The system Structure of Unix OS are as follows: 

UNIX is a family of multitasking, multiuser computer operating systems developed in the mid 1960s at Bell Labs. It was originally developed for mini computers and has since been ported to various hardware platforms. UNIX has a reputation for stability, security, and scalability, making it a popular choice for enterprise-level computing.

The basic design philosophy of UNIX is to provide simple, powerful tools that can be combined to perform complex tasks. It features a command-line interface that allows users to interact with the system through a series of commands, rather than through a graphical user interface (GUI).

Some of the key features of UNIX include:

  1. Multiuser support: UNIX allows multiple users to simultaneously access the same system and share resources.
  2. Multitasking: UNIX is capable of running multiple processes at the same time.
  3. Shell scripting: UNIX provides a powerful scripting language that allows users to automate tasks.
  4. Security: UNIX has a robust security model that includes file permissions, user accounts, and network security features.
  5. Portability: UNIX can run on a wide variety of hardware platforms, from small embedded systems to large mainframe computers.
  6. Communication: UNIX supports communication methods using the write command, mail command, etc.
  7. Process Tracking: UNIX maintains a record of the jobs that the user creates. This function improves system performance by monitoring CPU usage. It also allows you to keep track of how much disk space each user uses, and the use that information to regulate disk space.

Today, UNIX is widely used in enterprise-level computing, scientific research, and web servers. Many modern operating systems, including Linux and macOS, are based on UNIX or its variants.

Figure – system structure  

Figure – kernel and its block diagram 

This diagram shows three levels: user, kernel, and hardware. 


Difference between Unix and Linux

Linux is essentially a clone of Unix. But, basic differences are shown below: 

Linux Unix
The source code of Linux is freely available to its users The source code of Unix is not freely available general public
It has graphical user interface along with command line interface It only has command line interface
Linux OS is portable, flexible, and can be executed in different hard drives Unix OS is not portable
Different versions of Linux OS are Ubuntu, Linux Mint, RedHat Enterprise Linux, Solaris, etc. Different version of Unix are AIS, HP-UX, BSD, Iris, etc.
The file systems supported by Linux are as follows: xfs, ramfs, vfat, cramfsm, ext3, ext4, ext2, ext1, ufs, autofs, devpts, ntfs The file systems supported by Unix are as follows: zfs, js, hfx, gps, xfs, vxfs
Linux is an open-source operating system that was first released in 1991 by Linus Torvalds. Unix is a proprietary operating system that was originally developed by AT&T Bell Labs in the mid 1960s.
The Linux kernel is monolithic, meaning that all of its services are provided by a single kernel. The Unix kernel is modular, meaning that it is made up of a collection of independent modules that can be loaded and unloaded dynamically.
Linux has much broader hardware support than Unix. Unix was originally designed to run on large, expensive mainframe computers, while Linux was designed to run on commodity hardware like PCs and servers.
User Interface of Linux is Graphical or text-based. User Interface of unix is text-based.
Command Line Interface of Linux is Bash, Zsh, Tcsh. Command Line Interface of unix is Bourne, Korn, C, Zsh.

Advantages of UNIX:

  1. Stability: UNIX is known for its stability and reliability. It can run for long periods of time without requiring a reboot, which makes it ideal for critical systems that need to run continuously.
  2. Security: UNIX has a robust security model that includes file permissions, user accounts, and network security features. This makes it a popular choice for systems that require high levels of security.
  3. Scalability: UNIX can be scaled up to handle large workloads and can be used on a variety of hardware platforms.
  4. Flexibility: UNIX is highly customizable and can be configured to suit a wide range of needs. It can be used for everything from simple desktop systems to complex server environments.
  5. Command-line interface: UNIX’s command-line interface allows for powerful and efficient interaction with the system.

Disadvantages of UNIX:

  1. Complexity: UNIX can be complex and difficult to learn for users who are used to graphical user interfaces (GUIs).
  2. Cost: Some UNIX systems can be expensive, especially when compared to open-source alternatives like Linux.
  3. Lack of standardization: There are many different versions of UNIX, which can make it difficult to ensure compatibility between different systems.
  4. Limited software availability: Some specialized software may not be available for UNIX systems.
  5. Steep learning curve: UNIX requires a certain level of technical knowledge and expertise, which can make it challenging for novice users.


In this article we discussed Unix which is developed in the 1970s, the foundational operating system behind Linux and macOS. Emphasizing simplicity and a command-line interface, Unix’s multitasking, multiuser structure boasts stability, security, and scalability. It uses a kernel, shell commands, and an application layer. Despite its complexity, Unix remains a powerful choice for enterprise computing.

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