- UNIX is a heavy-weight operating system for big computers
- UNIX is complicated
- UNIX is hard to use
- UNIX has been created by SUN, IBM, HP, and other large companies
- UNIX is monolithic
- UNIX was developed on small machines and became popular on the "killer micros". UNIX dialects now run on everything from a watch to a supercomputer.
- UNIX is based on simple and elegant principles (but has added some cruft over the years).
- UNIX is not particularly hard to use (compared to the power it gives to the user), but has a reasonably steep learning curve. It's not a "show-me" operating system, but a "tell me" operating system (contrast Windows!).
- UNIX has been created in a research environment, and much of it has been developed in informal settings by hackers. Much of the impetus for UNIX comes from free versions (Linux, NetBSD, OpenBSD, FreeBSD), although many companies contribute to its development.
- Many UNIX kernels are monolithic, but the UNIX system is extremly modular.
- A very portable operating system (many architectures).
- Written in a "high-level" language (C).
- Small (for what it does):
- In 2025 the Linux kernel had 40 million lines of code.
- Windows 10 had (estimated) 50 million lines of code.
- Modular (though often on a monolithic kernel)
- Separate windowing system and window managers
- Various desktop solutions (CDE, KDE, Gnome)
- Toolbox philosophy: Combine (lots of) simple tools
- Underneath: Strong and simple abstraction (everything is a file)
- GNU/Linux combines the Linux kernel with the GNU project's collection of software.
- Read the first paragraph of
The Rise and Fall of the Roman Empire again, with the following
phrase replacements:
Rome => UNIX town => operating system Italy => Bell labs years => months wars => versions United States => UNIX implementations government => kernel Romans => UNIX developers English => Java Spanish => C++ French => AdaRome went from being a small town in Italy to being the center of a vast empire. This took hundreds of years and many wars. Rome was a lot like the present day United States - their government (for a while) but, most importantly, our attitude. The Romans were just like us in that they wanted it ALL. Our language, English, (and Spanish and French) comes from their language.UNIX went from being a small operating system in Bell labs to being the center of a vast empire. This took hundreds of months and many versions. UNIX was a lot like the present day UNIX implementations - the kernel (for a while) but, most importantly, our attitude. The UNIX developers were just like us in that they wanted it ALL. Our language, Java, (and C++ and Ada) comes from their language.
- See also http://www.levenez.com/unix/
- Read the history
- Pragmatic high level language:
- Handles characters, numbers, addresses as implemented by most computers
- Small core language, much functionality provided by libraries (mostly in C!)
- Compilers are easy to write
- Compilers are easy to port
- Even naive compilers produce reasonably decent code
- Hacker-friendly
- Straightforward compilation (nothing is hidden)
- Compact source code (fewer keystrokes, fast to read)
- Typed, but not a bondage-and-discipline language
- Adequate support for building abstractions
- Structures (composing objects), unions, enumerations
- Arrays and pointer
- Support for defining new types
- POSIX is a set of standards defined by the IEEE based on the Unix operating system. It defines a standard operating system interface and environment, including system calls, libraries, and utility programs. This allows developers to write code that can be compiled and run on any POSIX-compliant system without significant modifications.
Back row:
Ken Thompson
- B, UNIX;
Denis Ritchie
- C, UNIX;
Brian Kernighan
- awk
Middle row:
Bill Joy
- vi, BSD, SUN;
James Gosling
- emacs, Java;
Eric Allman
- sendmail;
Jon Postel
- Internet
Front row:
Richard Stallman - FSF, GNU;
Linus Torvalds - Linux, git;
Alan Cox
- Linux, Redhat;
Avie Tevanian
- OS X