Search wikipedia on topic : UNIX
Overview
Portable - written in C
Multi-user
Multi-tasking
Time-sharing
Interactive
File-system
- Hierarchical
- Flexible permissions - user,group,other
- Large utility library
- Scripting language to couple utlities together
Command-line interpreter
- Interactive
- User-friendly
- Redirection - simplified notation for accessing files.
- Pipes - provides coupling of data stream between commands.
- History - recall of commands
- Scripting - flow of control
- User configurable
History
Bell labs(AT&T), MIT, G.E. - Multics (mid 60s)
for Mini-computers < $1,000,000 - not mainframes.
Stripped down version of Multics - UNICS - pun? - mid-1960's
Ken Thompson, Dennis Richie, M.D. McIlroy, J.F. Ossanna
1972 - rewritten in C.
1975 - released as source code to various Universities.
- AT&T - Version 7
- University of Berkeley - Berkeley
1982 - AT&T broken up (anti-trust)
Bell Labs starts marketed to companies.
- AIX - IBM
- HP-UX
- Xenix - Microsoft, SCO
- Solaris System V - Sun Microsystems.
- etc.
Linux
- Look and feel
and Lotus vs. Borand
- Linux Is Not UniX - not build on original source code.
- kernel - written by Linus Torvalds
- GNU utilities, GNU not Unix(GNU) - Richard Stallman and many others.
- Like Unix - several Major branches and many minor.
POSIX (1988) - IEEE standard - guides various versions to have some consistency.
- COSE - Common Open Software Environment (COSE)
- Single UNIX Specification (SUS) - by the Open Group.
- Merged again under POSIX (1998) by Open Group and IEEE.
- becoming the Open Group Base Specification.
- Still appears as POSIX on most systems.
- Many systems have own command and POSIX version.