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Unix
"Those who don't know Unix are doomed to reinvent it, poorly." --obligatory quote by Henry Spencer
Unix (plurar Unixes or Unices) is an old operating system developed since 1960s as a research project of Bell Labs, which has become one of the most influential pieces of software in history and whose principles (e.g. the Unix philosophy, everything is a file, ...) live on in many so called Unix-like operating systems such as Linux and BSD (at least to some degree). The original system itself is no longer in use (it was later followed by a new project, plan9, which itself is now pretty old), the name UNIX is nowadays a trademark and a certification. However, as someone once said, Unix is not so much an operating system as a way of thinking.
In one aspect Unix has reached the highest level a software can strive for: it has transcended its implementation and became a de facto standard. This means it has become a set of interface conventions, "paradigms", cultural and philosophical ideas rather than being a single system, it lives on as a concept that has many implementations. This is extremely important as we don't depend on any single Unix implementation but we have a great variety of choice between which we can switch without greater issues. This is very important for freedom -- it prevents monopolization -- and its one of the important reasons to use unix-like systems.
The main highlights of Unix are possibly these:
- Unix philosophy: a kind of general mindset of software development, usually summed up as "do one things well" (rather than "do everything but poorly") and "make programs work in collaboration with other programs", advising on using universal text interfaces for communication etc. This often comes with the idea of pipes, a way of chaining programs (typically using the pipe
|operator, hence the name) by sending one program's output to other program's input. - everything is a file: Unix chose to use the file abstraction to enable universal communication of programs with hardware and among themselves, i.e. on unices most things such as printing, reading keyboard, networking etc. will be likely implemented as reading or writing to/from some special (sometimes just virtual) file. This has the advantage of being able to just use some file reading library or syscall, not having to access physical memory bits in memory, which may be difficult, unsafe etc.
- Text centrism (great command line preference), value on portability (even over performance), sharing of source code, freedom of information and openness, connection to hacker culture, valuing human time over machine time, ...
- ...
Unix is greatly connected to software minimalism, however most unices are still not minimalist to absolute extreme and many unix forks (e.g. GNU/Linux) just abandon minimalism as a priority. So the question stands: is Unix LRS or is it too bloated? The answer to this will be similar to our stance towards the C language (which itself was developed alongside Unix); from our point of view Unix -- i.e. its concepts and some of their existing implementations -- is relatively good, there is a lot of wisdom to take away (e.g. "do one thing well", modularity, "use text interfaces", ...), however these are intermixed with things which under more strict minimalism we may want to abandon (e.g. "everything is a file" requires we buy into the file abstraction and will often also imply existence of a file system etc., which may be unnecessary), so in some ways we see Unix as a temporary "least evil" tool on our way to truly good, extremely minimalist technology. DuskOS is an example of operating system more close to the final idea of LRS. But for now Unix is very cool, some Unix-like systems are definitely a good choice nowadays.
History
In the 1960s, Bell Labs along with other groups were developing Multics, a kind of operating system -- however the project failed and was abandoned for its complexity and expensiveness of development. In 1969 two Multics developers, Ken Thompson and Dennis Ritchie, then started to create their own system, this time with a different philosophy; that of simplicity (see Unix philosophy). They weren't alone in developing the system, a number of other hackers helped program such things as a file system, shell and simple utility programs. At VCF East 2019 Thompson said that they developed Unix as a working system in three weeks. At this point Unix was written in assembly.
In the early 1970s the system got funding as well as its name Unix (a pun on Multix). By now Thompson and Richie were developing a new language for Unix which would eventually become the C language. In version 4 (1973) Unix was rewritten in C.
Unix then started being sold commercially. This led to its fragmentation into different versions such as the BSD or Solaris. In 1983 a version called System V was released which would become one of the most successful. The fragmentation and a lack of a unified standard led to so called Unix Wars in the late 1980s, which led to a few Unix standards such as POSIX and Single Unix Specification.
For zoomers and other noobs: Unix wasn't like Windows, it was more like DOS, things were done in text interface -- if you use the command line in "Linux" nowadays, you'll get an idea of what it was like, except it was all even more primitive. Things we take for granted such as a mouse, copy-pastes, interactive text editors, having multiple user accounts or running multiple programs at once were either non-existent or advanced features in the early days. Anything these guys did you have to see as done with stone tools.