Is Not Unix


As a tech enthusiast, I have always been fascinated by operating systems and their functionalities. One of the most famous and influential operating systems in the world is UNIX. However, in this article, I want to discuss something that is often misunderstood – “is not UNIX.”

Understanding the Origins of UNIX

UNIX was developed in the 1960s and 1970s at Bell Labs. It was designed to be a portable, multi-user, and multitasking operating system. UNIX became popular due to its simplicity, flexibility, and powerful command-line interface. It quickly gained traction in universities and research institutions, and its influence can still be seen in modern operating systems today.

The Rise of UNIX-Like Operating Systems

Over time, many operating systems have evolved and been inspired by UNIX. These operating systems are often referred to as “UNIX-like” or “UNIX-based.” They borrow many concepts and principles from UNIX but may not be fully compliant with the Single UNIX Specification.

For example, one of the most well-known UNIX-like operating systems is Linux. Linux was developed as a free and open-source alternative to UNIX. It shares many similarities with UNIX, such as the command-line interface and a focus on simplicity and modularity. However, Linux is not a certified UNIX operating system.

The Differences Between UNIX and UNIX-Like Systems

While UNIX and UNIX-like systems share many similarities, there are some key differences that set them apart. These differences stem from the fact that not all UNIX-like systems are fully compliant with the Single UNIX Specification, which defines the requirements for an operating system to be considered UNIX.

Some of the differences between UNIX and UNIX-like systems include:

  1. Certification: UNIX systems must pass a certification process to be considered true UNIX, while UNIX-like systems are not certified.
  2. API Compatibility: UNIX-like systems may not fully adhere to the UNIX standard API, leading to some incompatibilities with software written for UNIX.
  3. Kernel Variations: UNIX-like systems often have different kernels with their own unique features and implementations.

Why “is not UNIX” Matters

Understanding the distinction between UNIX and UNIX-like systems is important for developers and system administrators. It helps clarify the level of compatibility and the specific features and limitations of different operating systems.

For example, when developing software, knowing the target platform’s adherence to the UNIX standard can dictate the compatibility and portability of the software. Similarly, system administrators need to be aware of the nuances of different operating systems to choose the right one for their specific needs.


In conclusion, while UNIX-like systems have undoubtedly made a significant impact on the computing world, it’s essential to recognize that not all UNIX-like systems are UNIX. UNIX remains a certified operating system that adheres to a specific set of standards, while UNIX-like systems vary in their compliance and implementation.

As a tech enthusiast, exploring the intricacies of UNIX and its derivatives has been a rewarding journey. Remember, while UNIX-like systems may share similarities with UNIX, they are distinct in their own right.