wth (wth...@pl.jaring.my) wrote:
: my college is using 'System V' version of UNIX...
: how old was this?
.... more than a quarter century.
SysV (or AT&T) and BSD are the two major families
of Unix variants. Most good books on Unix have a
small summary of the history of Unix in the introduction,
the first chapter or in some appendix.
(I can't possibly do those histories justice
-- see the end of this message for a better
There have been many versions and implementations of
SysV -- most recent ones are SVR4 (release 4) --
the most recent of those I think is SVR4.4.
Coincidentally BSD is also at version 4.4. However
Several BSD derivatives that are based on BSD 4.4
have different version numbers:
BSDI/OS -- from Berkeley Design Systems Inc.
FreeBSD, NetBSD, and OpenBSD each have their
own version numbers.
SunOS 4.1.4 is the latest version of Sun's BSD derived
OS. SunOS isn't being developed further -- only the
occasional patch/fix released is made.
Solaris is is Sun's AT&T derivative -- made only a few
years ago as part of a major restructuring. It is
currently at version 2.51 or 2.6.
: how about HP-UX?
HP-UX is HP's version of AT&T SysV. It is currently
at version 10.x (or is it 11.x).
: why is there so many versions of UNIX out there?
Because there are so many different computer architectures
out there -- and there are so many different ways to do
the same basic thing on any given platform.
: what are all these :
: System IV, System V, HP-UX, BSD UNIX, XENIX, LINUX, XXXXXX.....
There is no Sys IV that I've ever heard of. There was
System 6 (never left AT&T's site so far as I know) and
System 7 (about 20 years ago).
We've already discussed System V (aka SysV or SVRx --
where SVR3.2 and SVR4.4 are most common instances).
BSD and all its derivatives (BSDI/OS (formerly BSD386),
FreeBSD, NetBSD, OpenBSD, 386/BSD (called Jolix by some))
derive from a set of enhancements to an early AT&T
Unix that were done by the Computer Science Research
Group (CSRG) at the University of California,
BSD offered the early implementations of the TCP/IP
networking code and added the rsh, rcp and rlogin
commands. BSD stands for "Berkeley Software
Xenix was an early attempt by Microsoft to put Unix on
IBM PC hardware. It is, if I recall, derived from System 7
sources -- as they were still small enough to run on a
PC. The very early Xenix ran on XT systems -- but most
versions required a 286 or better.
Xenix was later acquired by or licensed to SCO (Santa Cruz
Operations). Microsoft owned a big chunk of SCO for a
long time -- I don't know if they still do.
SCO also produces the ODT (Open DeskTop) which is an
SVR4 derivative. They also now own UnixWare (formerly
owned by Novell) and they hold the copyright to the
original AT&T Unix Source code -- after it went through
USL (Unix System Laboratories -- an organization spun
off of or founded by AT&T and various Unix licensees) --
and after Novell bought USL/Unix.
Novell gave the trademark on the term "Unix" to X/Open
-- an industry consortium.
SCO's ownership is further diluted by the existence of
several "perpetual and unlimited" licenses held by
companies like Sun.
Linux is an implementation of the POSIX specification
which wasn't derived from any of the early source code.
POSIX was an attempt by the U.S. federal government to
create a standard for their purchasing/bid requirements.
It resulted in a specification that could be met by
operating systems such as VMS and MVS (both of which have
POSIX subsystems or configurations).
The Linux project was started by Linus Torvalds, then a
student at the University of Helsinki in Finland. He
started it as an exercise to learn more about the low-level
architecture of the Intel 386 chip -- and did his early work
Minix is a vaguely Unix like operating system written by
Andrew S. Tannebaum -- to serve as an example for his
classes and books on "Modern Operating Systems." Minix
is a "microkernel" design that has been ported to the
XT and AT, and to Macs, Amigas, and a few other micros.
Linux uses a "monolithic" (non-microkernel) design --
although advances in loadable modules, and automatically
loaded modules (kerneld) -- and the work by Apple Computers
Inc to fund the development of mkLinux (Linux running over
a CMU "Mach" microkernel) makes this an increasingly moot
Strictly speaking Linux is just a kernel. Linus Torvalds
continues to manage the project accepting source code
patches and new modules from basically anyone who wants
to send in usable code. He's completed his post-graduate
work and has accepted a position with a start-up in the
Silicon Valley, near San Francisco, California (where I
In the broader sense "Linux" refers to any of the 40, 50,
or larger number of "distributions" -- collections of software
that are bundled with a Linux kernel. If I wanted I could make
a collection of my own -- put it on an FTP site, start burning
CD's, give it a clever name.
What is remarkable about Linux is that this anarchy is
not only legal and acceptable to the copyright holders
(Linus T. and hundreds of others) -- but is actually
ENCOURAGED. Some of the popular Linux distributions are:
Red Hat, Slackware, Yggdrasil, Debian, and Caldera
... some of the more obscure or out-of-date are:
MiniLinux, DILinux/DOSLinux, Nascent, Bogus,
S.u.S.E., LaserMoon FT, SLS, TAMU, MCC Interim, etc.
Oddly enough the FreeBSD, NetBSD, and OpenBSD -- which
all splintered from the work of Mr. and Mrs. Jolitz --
called 386BSD -- have licensing terms that are at
least as liberal (arguably more so). Yet there are
far fewer sources of these. FreeBSD is readily
available from Walnut Creek -- the largest publisher
of CD software collections. Walnut Creek uses FreeBSD
as the server software for their FTP archives -- which is
almost certainly the largest and probably the busiest on
NetBSD is the most portable of the free *BSD's -- and is
available on PC, SPARC, Mac (68K), Amiga and other platforms.
Linux is gaining in portability with ports in progress for
MIPS, Alpha, SPARC, and Mac (PowerPC) platforms.
Linux has been considerably more popular -- and gained
considerably more media attention and notoriety -- than
all the other "free" versions of Unix. This results in
considerable acrimony and fans the flamewars in all the
Despite all the haggling between proponents and enthusiasts
of the Linux and *BSD groups there is considerable co-operation
among them. Just about any significant piece of free software
that is written for any one of them is ported to all the others.
There are *many* other Unix and Unix like operating
systems -- at least 680 (this is the number to which
the venerable C-Kermit -- Columbia University's
communications software -- has been ported). Some of
This isn't ready for wide use yet.
It is the penultimate product of the
Free Software Foundation -- the
kernel for their GNU project.
It is worth noting that about 90% of
almost any Linux distribution is software
from the GNU project. Some major components
from the *BSD groups are also FSF GNU
packages. (Notably the compiler!)
Richard Stallman, founder of the FSF,
embarked on this project a long time
ago (before Linus or the Jolitz' started
work on their projects).
His strategy was to create the best
set of utilities and tools first. Make
those available on as many platforms as
possible. Then use those to create a
kernel -- and thus create a complete
operating system that will be freely
(Some have argued that Linux/GNU has
already done this -- RMS and others
have argued that ... -- more acrimony
and debate -- but more co-operation
underneath it all, too)
HURD is based on the CMU (Carnegie
Mellon University) "Mach" microkernel.
(Yes, so is mkLinux -- mentioned ealier).
The Mach Microkernel is not a Unix
implementation. It is an OS that allows
one to "emulate" or "implement" a variety
of OS API's (Applications Programming
Interfaces) to run concurrently on the
There are many Unix variants built over
Mach. A few are QNX, Mt. Xinu, Chorus, and
Tenon Systems' MachTen.
One of the Unix variants for the Mac
(68K or PowerPC) platforms. This was
for a long time the only commercial
competitor to Apple's A/UX unix derivative
for their Mac platform.
This a Unix built over Mach with an
Object-oriented GUI built over that.
NeXT was founded by Steve Jobs after
he left Apple Computers (about a decade
ago). Originally a hardware company --
NeXT later ported his OS to the PC
architecture where it became a small
but interesting niche.
Sun also licensed/ported a version of
NeXTStep which is called "OpenStep."
There is a project to create a free
distribution of OpenStep -- which is
Most people think of X Windows as the
only GUI for Unix. This is really a
misnomer since X Windows is technically
a communications protocol -- which hosts
several GUI's including Motif and CDE and
which can support several graphical API's
including PeXlib, OpenGL and NeXTStep's
Steve Jobs later became a multi-billionaire
-- largely from his investment and work with
Pixar -- the makers of "Toy Story."
Recently, Jobs has rejoined Apple Computers
and is engineering a major comeback effort
As part of that deal Apple aquires NeXT
and will try to complete their "Copeland"
project -- which was a major
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