31 January, 2008

UNIX

The title speaks for itself...


The Original Unix
http://en.wikipedia.org/wiki/Unix_philosophy


"Unix is simple. It just takes a genius to understand its simplicity."
Dennis Ritchie


Dennis Ritchie invented the programming language; C, more commonly known in computer theory as a "System Implementation Language". With the aid of C, Dennis Ritchie, along with Ken Thompson, created the early versions of the original UNIX operating system at "Bell Labs".


Bell Labs was merged with AT&T in the early 80's, creating the company "AT&T Bell Laboratories". In 1996 AT&T spun off their technologies and organizations into "Lucent Technologies", but kept the services business within AT&T. But Lucent still used the line "Bell Labs Innovations" in their logo's. And in 2006, Alcatel and Lucent merged into the company "Alcatel Lucent".


Ritchie now works in the "Convergence, Software and Computer Science Laboratory" department for Alcatel Lucent, residing in the Bell Labs Laboratories building.


Just a brief little history of how much an IT company can reorganize and rebrand over a couple of decades, but Ritchie says it's been a good company and office to do his kind of work in despite all the administrative stuff.


Sections from the above text is taken from Ritchie's homepage, which also contains a lot of interesting material on UNIX and UNIX programming: http://www.cs.bell-labs.com/who/dmr/

The last official
UNIX from Bell Labs is known to most UNIX fanatics today as: "System V", from which the pre-decessors, the "UNIX Time Sharing System (1-7)" also spawned the various "Berkeley Software Distribution(s)" available today (FreeBSD, OpenBSD, etc), often referred to as "BSD Unix" because it shared some initial codebase with the original UNIX by AT&T/Bell Labs.
"UNIX System V" continued to release versions up to version 4 in 1988, but "UTSS" releases, went up to version 10 until 1989. "UNIX System V version 4" forked off both "Solaris" and the now commercially available "UnixWare" in the 90's. It is also the basis for later implementations of the "SysV runlevel init scripts" in BSD and Slackware Linux. Other Linux distro's also include the SysV init system, but a lot of them are heavily modified and customized.
A number of big corporations made their own proprietary UNIX flavours. IBM made the "AIX" system, SGI made the "IRIX" system and Hewlet Packard made the "HP-UX" system, of which I had some user-experience with while working in the WAN-sector.

Other Implementations

In 1987, the system called "MINIX" also saw the light of day, which is the source of inspiration for Linus Torvalds "Linux" announced in 1991. Linux was created on UNIX philosophy and design concepts, but NOT based, or forked in any way on the UNIX codebase what-so-ever. I cannot determine if MINIX is a complete original, or a fork. The "Linux-IS-UNIX" claim, is a common misconception, and probably the reason why so many UNIX codebase owners has tried to sue the Linux creator(s) the last decade, there was even written a report funded in large by Microsoft about the similarities between Linux and MINIX, almost accusing Linus for stealing his idea and basis for Linux entirely from MINIX, which turned out to be untrue (even noted by MINIX creator Andrew S. Tanenbaum on his MINIX website FAQ). On the other hand, MINIX is microkernel-based, and has absolutely nothing to do with the monolithic kernel base used in Linux, except for the fact that Linus used and studied MINIX while attending the University of Helsinki as he was developing Linux. AND.., MINIX started porting it's sourcecode to other archtitectures around 1991.., coincidence?
If you're confused about the word "kernel", you should read this.
If you're still confused, you probably won't understand most of this post at all.

Tanenbaum and Torvalds even had a well-known 'flamefest' in the early 90's concerning the "obsoleteness" of the
monolithic kernel design in Linux, compared to Tanenbaum's microkernel implementation in MINIX.
Lawsuits

The early 90's witnessed USL (Unix System Laboratories) bring a lawsuit against BSDi (Berkeley Software Design) claiming that BSD contained illegally obtained code from the proprietary NET-2 UNIX codebase.

The mid 90's also saw a flow of lawsuits brought against Linux contributors (primarily IBM and Novell) from
SCO, the company that owned the rights to the original UNIX codebase at the time, claiming
they used their licensed and copyrighted Unix code in their contributions. The codebase is currently owned by Novell, as a result of the court-cases, the copyrights were solidified under Novell, the creator of SuSe Linux, which is in large parts based on my favourite Linux distro; Slackware Linux ;P
Other systems based on original Unix


Another useful link in this context would be the OS developed at Bell Labs/Lucent Technologies, named "Plan 9". The project goal was to create UNIX in it's simplicity as originally intended in the early development stages, but for use in the modern world. It also incorporated a couple of new concepts alongside the classic UNIX implementations. This was in the "Lucent Technologies" era of Bell Labs in the late 90's. The first and second release were strictly commercial, but in 2000, the third release was made under an open source license, and all commercial interest in the project dropped. The project is now in it's fourth release. http://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs

And last, but not least, Dennis Ritchie created with the help of others, the last update of Plan 9, called "Inferno", which aims at providing a POSIX environment based on original UNIX concepts on a range of different devices, architectures and platforms (a wide specter of platforms actually: WinNT/2000/XP, Irix, Linux, BSD and Solaris). Worth mentioning about this project, is both the actual system changes themselves (filesystem,core), and it's "Dis Virtual Machine" kernel concept and it's accompanying programming-language "Limbo" which utilize JIT compilaion ("Just-In-Time", or "on-the-fly" compilation of object code). Inferno is also the first POSIX system from Bell Labs which seems successfull with the dual-licensing model (both commercial, "without copyleft" and Free Software (FSF,GPL), "with copyleft"). http://en.wikipedia.org/wiki/Inferno_%28operating_system%29

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