Notes on the Early History of Unix, BSD and Vi

Pavol Kutaj

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Dec 11, 2023

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History of Unix

1. The history of Unix is similar to the history of the personal computer in that both were developed by companies that were not primarily focused on those products. AT&T developed Unix, while IBM developed the personal computer.
2. The rise of the personal computer was driven by cheap third-party clones, while the rise of Unix was driven by a dedicated community of programmers who had access to the source code and were able to create their own distributions and mutations.
3. Unix was developed around 1970, while the IBM PC was released around 1980.
4. From Unix, BSD was born, then Mac OS, and later Linux. Linux itself is only the kernel, and to get a functional operating system, you need a system of applications that make the operating system functional. This system of applications that runs around the kernel and creates a system that can be used is called a distribution.
5. Examples of Linux distributions include Ubuntu, Debian, and Red Hat. There is also a very lightweight distribution called Alpine.
6. The diversity of Linux is due to the history and diversity of Unix, specifically the development of the 1970s when Unix was introduced to the University of California, Berkeley, and began to slowly mutate into different versions in an uncontrolled direction. This is the beginning of diversity and chaos.

The early years of Unix

1. The first important mention of Unix was in 1973 at the ACM conference, where it was presented by the authors Dennis Ritchie and Ken Thompson.
2. Professor Fabry from Berkeley was able to get access to Unix because AT&T was required to provide Unix for legal reasons. AT&T was involved in anti-trust cases and could only profit from telecommunications system software if they sold it at a very low price. Therefore, Fabry requested the system and was provided with it.
3. It is important to note that AT&T is located on the East Coast, in New Jersey, while Berkeley is located on the West Coast, in California.
4. One of the first applications developed on early Unix was the Ingres database system. PostgreSQL is a direct descendant of this database.
5. Ken Thompson himself came to Berkeley for a year and began working on a Pascal compiler for Unix. He did not finish the project, but graduate students took it over, one of whom was Bill Joy.
6. It is important to remember that the machine on which Unix ran at the time of its creation, the PDP-11, was very small compared to the PDP-10 or IBM machines. It was simply a relatively inexpensive machine on which an experimental operating system was running, created somewhere in the back office of a large company. This was the beginning of hacker culture.
7. Unix had a shell, a terminal, and a very weak editor called ed.
8. The first editor was one-dimensional, meaning that you could only see one line at a time and you could only move in one direction, word by word. It was like a typewriter, except that you couldn’t see what was above or below. Try typing ed in a terminal and you will see for yourself.
9. In 1975, the Teletype came out, which had a glass screen and was able to display in two dimensions, meaning the entire page, and it was possible to move the cursor. The first editor, ed, was no longer sufficient.
10. The first successor to ed was called EM — editor for mortals. It was developed in London.
11. Unix was distributed not as binary code with an installer, but as the entire source code. This meant that it was actually open source. So, when the author of a new editor wanted to see how the first editor worked, he just had to look at the code and improve it a bit. This openness and modifiability is the beginning of a new community and the driving force behind the success of Unix.
12. This community was of a university type, and the success of Unix was also enabled by the low cost of hardware and the easy availability of software.
13. The EM editor came to Berkeley from London, and when Bill Joy saw how it worked, he added his own improvements and created the third editor, EX, which stands for “Extended”.
14. EX had an open or visual mode, in which the program was opened on the entire glass screen of the terminal, and it was possible to edit the entire file in two dimensions and move around it in all four directions. This is the birth of the cult editor vi.
15. In 1977, the Berkeley 1BSD distribution was created. It included a Pascal compiler, the ex editor, the A-Shell, and one game called Trek.
16. In general, what matters to a Unix user is the application that can be used with the shell.
17. BSD is not the first distribution, nor is it the beginning of the tradition of software distribution. It did not create or define the category of distribution — it simply used existing established trends. It is important because of the influence it has created, namely by branching out the family tree of which it is a part.
18. The vi editor is the same as ex, except for its visual mode.
19. In BSD2, a new shell, the c-shell, was also added.
20. The shell and terminal are not an integral part of the Unix kernel. They are simply ordinary programs that run on the system. Therefore, they can be replaced with something else. For example, bash can be replaced with zsh or fish.
21. Another important improvement is history. In addition to history, there is also job control, which means sending tasks to the background while the dialogue remains under the control of the user. Therefore, Unix also has multitasking in 1979. PC and DOS do not exist yet.

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