The History of UNIX and Linux
UNIX is an operating system that was developed in the late 1960s.
The computers of that era were large machines operated through multiple terminals.
These terminals consisted only of a screen and keyboard and had no processing unit of their own.
Until the mid-1960s, data was primarily processed using punched cards.
To make better use of the available computing power, so-called time-sharing systems were developed.
In these systems, computing time was divided into small time slices, allowing multiple programs to appear to run simultaneously.
This principle is now known as multitasking.
Since multiple users could work on the same computer at the same time, so-called multi-user systems emerged.
Different rights and permissions could be assigned to individual users.
The development of a multi-user system called MULTICS (Multiplexed Information and Computing Service) began as a joint project of Bell Laboratories, MIT, and General Electric.
The project was later discontinued.
In 1969, Ken Thompson, an employee of Bell Labs, developed a smaller operating system on a DEC PDP-7.
Together with Dennis Ritchie, he designed a hierarchical file system as well as mechanisms for process and memory management.
Brian Kernighan jokingly referred to the new system as UNICS (Uniplexed Information and Computing Service), inspired by MULTICS.
This name later evolved into UNIX.
As early as 1971, UNIX was being used productively within Bell Labs and was ported to the more powerful PDP-11.
Since UNIX was originally written in assembly language, porting it to other computers was difficult.
Therefore, Dennis Ritchie developed the C programming language, which was based on the language B.
By 1973, most of UNIX had already been implemented in C.
In 1974, Bell Labs licensed the UNIX source code to universities.
As a result, the system spread rapidly and various UNIX versions emerged.
At the University of California, Berkeley, a separate UNIX variant was developed.
It later became known as BSD (Berkeley Software Distribution).
Modern operating systems such as FreeBSD, OpenBSD, and NetBSD originated from BSD.
In 1979, the first widely distributed BSD version was released.
At the same time, UNIX was increasingly marketed and licensed by AT&T.
While software was often freely exchanged in source code form during the 1970s, many companies began in the late 1970s and early 1980s
to distribute their programs only under restrictive licenses.
UNIX was also offered as proprietary software from that point on.
To preserve the idea of free software, Richard Stallman founded the GNU Project in 1983.
GNU is a recursive acronym that stands for "GNU's Not UNIX".
The goal of the project was to develop a completely free operating system modeled after UNIX.
In addition to BSD, several other UNIX systems existed by the late 1980s.
For example, Sun Microsystems developed the Solaris operating system, which was based on UNIX System V.
In 1989, System V Release 4 (SVR4) was released, aiming to unify many developments from the various UNIX variants.
Many modern UNIX systems still follow these standards today.
In 1991, the Finnish student Linus Torvalds began developing a free UNIX-like operating system kernel.
One of his sources of inspiration was Minix, a UNIX-like educational operating system developed by Andrew S. Tanenbaum.
He used the GNU C Compiler and freely published his source code on the Internet.
By combining the Linux kernel with the tools of the GNU Project, a complete free operating system was created.
For this reason, the term GNU/Linux is also frequently used.
Over time, numerous Linux distributions emerged, combining the Linux kernel with different software packages, package management systems, and desktop environments.
Some of the best-known distributions include Debian, Ubuntu, Fedora, openSUSE, Arch Linux, and Linux Mint.
They differ in their target audience, release model, and software selection.
Today, large parts of the world’s server infrastructure run on UNIX or Linux systems.
In addition, Linux forms the foundation of many other operating systems, including Android.
