History (Introduction)
Ken Thompson working at Bell Labs in 1969 wanted a small MULTICS for his DEC PDP-7
He wrote UNIX which was initially written in assembler and could handle only one user at a time
Dennis Ritchie and Ken Thompson ported an enhanced UNIX to a PDP-11/20 in 1970
Ritchie ported the language BCPL to UNIX in 1970, cutting it down to fit and calling the result “B”
In 1973 Ritchie and Thompson rewrote UNIX in “C” and enhanced it some more
Since then it has been enhanced and enhanced and enhanced and …
See Wang, page 1 for a brief discussion of UNIX variations
POSIX (potable operating system interface) - IEEE, ANSI