Unix history and foundation of Linux (simplified)
1969: a UNIX like OS on PDP 7 was written by Ken Thompson in Bell Labs
It was single user, non-multitasking, written in assembler;
1973: C programming language by Dennis Ritchie in Bell Labs;
1975: First widely available version of UNIX (written in C);
Late seventies: two main stream UNIX distributions - System V from Bell Labs
and Berkeley release.
Eighties: commercial UNIX operating systems: DEC, Sun, IBM, etc.
1985: GNU, the Free Software Foundation, is founded (Richard Stallman)
1991: Starting of the Free Family Berkely like OS, BSD, (NetBSD, FreeBSD, OpenBSD).
1991: Finnish graduate student Linus Torvalds announces release of Linux
based on GNU tools.
Now days: numerous distributions of Linux; the fastest developing OS;
accepted by some commercial UNIX vendors (IBM, Sun, HP, SGI).