Unix vs. Linux: What’s the Difference?

Unix and Linux are notable operating systems that have given rise to numerous variants. Linux itself is derived from Unix. As their names indicate, Unix and Linux are extremely similar, but what are the differences?

In this article, we share the most important differences between Unix and Linux. Let’s get into it!

Unix vs. Linux: Side-by-Side Comparison

Unix vs. Linux: What’s the Difference?

Unix is a grandfather operating system that has given rise to many of the modern OS and software applications we encounter today, including Linux! But these two giants of computing still have important differences that affect how they perform and the applications they are used for.

Here are the most important differences between Unix and Linux.

Operating System Origins and Development

Unix is one of the world’s first operating systems. It was originally developed in 1970 as a private OS for Bell Labs, which later was broken up into AT&T and other companies. Ken Thompson, a computer scientist, and others developed Unix, which was released in 1973. Bell Labs also developed the C programming language, which is foundational for all other operating systems. 

Linux is 20 years younger than Unix. Linus Torvalds used MINIX, a Unix-like OS, as the basis of Linux. The Linux kernel that Torvalds developed has since given rise to numerous derived distributions.

Licensing and Trademarks

Linux is well-known for being completely open-source (General Public License), but Unix is largely proprietary. The only open-source version of Unix is under the BSD license. Otherwise, Unix is held under the System-V Unix proprietary commercial license. 

Linus Torvalds owns the Linux trademark, while the UNIX trademark is held by the Open Group. These trademarks are used with certified operating systems. 

The Kernel

The Linux kernel is monolithic, meaning that the entire OS is contained within the kernel, defining the entire virtual interface of a computer. Unix can also be monolithic, but it is also a microkernel, where only the most basic mechanisms are covered by the OS.

Unix operating systems can also be a hybrid of these two kernel types. 

Software Ecosystem

Both operating systems have given rise to numerous operating systems, with Linux having over 600 active distros. Because Linux is a monolithic kernel, developers can work with it more easily, adding and removing loadable kernel modules (LDM) dynamically in contrast to the static linking of new systems and modules with Unix. 

Support

Linux is also open-source and actively supported by a diverse and collaborative community. The proprietary nature of Unix means that only a handful of companies own and maintain their versions of the OS. 

What is Unix?

Unix is an ecosystem of open-source and proprietary operating systems that is more than 50 years old. They have been developed from AT&T Unix, which was created by Bell Labs as an internal OS in the 1960s. The original developers at the Bell Labs research center were led by Ken Thompson, Dennis Ritchie, and others.

The licensed AT&T version of Unix was eventually sold by AT&T to Novel, and later, The Open Group. 

The Open Group oversees the Single Unix Specification (SUS). Version 7 of the SUS has given rise to many open-source and proprietary versions.

Notable Unix versions include:

• BSD from the University of California, Berkeley
• AIX developed by IBM
• Xenix by Microsoft
• SunOS/Solaris developed by Sun Microsystems

Unix operating systems are comprised of the Unix filesystem, pipes or pipelines that facilitate inter-process communication and the Unix shell that serves as the scripting and command language for the OS. In addition, the Unix kernel serves as a master control for the software, starting and stopping programs and managing the low-level tasks that many software applications have in common. As it was written in the C programming language, it is compatible with a wide range of platforms.

Unix was designed primarily as a platform for computer programmers to develop software, but it has largely been appropriated by academics and hobbyists who have customized and innovated it collaboratively over time. Collaborators increased the portability of Unix as well as its capacity for multi-user or multi-tasking use. 

In the 1980s, many users thought that Unix could become a universal OS as the C programming language it was written in was one of the primary programming languages used by universities, government institutions, and companies. This enabled Unix to be ported to a wide range of devices.

Because Unix is built around a kernel, a core program that forms the operating system’s backbone, it is highly customizable and has been adapted and extended, with the most notable example being the Unix-like operating system that includes Linux. Many of these operating systems are quite different from Unix, but they behave similarly at the command or shell level. 

What is Linux?

Linux is an ecosystem of open-source and private operating systems that are all based on the Linux kernel. The Linux kernel is a Unix-like operating system kernel that was authored by the Finnish-American developer, Linus Torvalds, in the early 1990s.

Software companies and developers have packaged Linux in a variety of distributions (“distros”) that include the Linux kernel plus proprietary supporting software and libraries.

Well-known Linux distros include:

• Ubuntu
• Fedora
• Linux Mint
• Debian
• ChromeOS

Linux can be run on a wide range of devices. Anyone can work with the kernel and make an operating system for specific or general use. The methodical and scalable architecture of its filesystems is advantageous for servers. Devices that require graphics like PCs and laptops typically use a windowing system like Wayland as a user interface.

Linus Torvalds developed Linux in 1991 for computers with the Intel x86 architecture. It is based on the Unix operating system he encountered while he was a computer science student at the University of Helsinki. It was not intended to be named after him, but a friend who uploaded his OS called it “Linux” after Linus. 

Its enthusiastic reception led to developers from around the world porting it to many other operating systems. You’ll find Linux-based operating systems being used anywhere from cheap Chromebooks to supercomputers.  

Interestingly, Linux can also be run on devices that have an inbuilt OS in their firmware. It now plays a prominent role in commercial smart technology as diverse companies can pick up the Linux kernel and adapt it to their requirements quickly and reliably. You’ll find Linux being used in devices that include routers, IoT devices, TVs, cars, and game consoles. 

Linux has been a massive success because of its 100% free and open-source GPLv2 licensing, which has encouraged collaboration from around the world. Anyone can take the Linux source code and do something with it. Operating systems and software applications that have been developed using Linux may also be distributed commercially as well as for free. 

Unix vs. Linux: 5 Must-Know Facts

• MacOS is an example of a Unix-like operating system.
• Unix-like operating systems are hard for malware to infect because the source code is not in the public domain. 
• With the Unix microkernel, Unix handles core operating system processes, but other software is used to manage other processes that a monolithic OS would handle. 
• Unix cannot support as many filesystems as Linux.
• Android and ChromeOS are Linux-based operating systems.

Final Thoughts 

Linus Torvald’s friendly penguin, Linux, is much more widely known, but Unix is the progenitor OS that has influenced every OS that has followed its 1970 release. Its development at Bell Labs, along with the C programming language, paved the way for modern software development, and its derivative operating systems are still in active use today. 

The image featured at the top of this post is ©Stanislaw Mikulski/Shutterstock.com.