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498 UNIXOPERATINGSYSTEMIn addition, it was able to be networked and operate as a
networked system. All of this caught the eye of the U.S.
Defense Advanced Research Projects Agency (DARPA), an
agency of the Department of Defense (DoD), which was in-
terested in seeing an its new Transmission Control and In-
ternet Protocols (TCP/IP) running on multiple hardware
solutions. The DoD had pretty much decided on the VAX
as its primary platform and was in search of a suitable
operating system.
Among its desires was an operating system that sup-
ported virtual memory (the ability to use the disk as a
virtual memory image, thus effectively significantly
expanding available memory). VMS (Virtual Memory
System—the native operating system for the VAX pro-
duced by DEC itself) was an obvious choice. So was BSD
Unix. In addition, because Unix was written in a portable
language such as C, Unix had the advantage of being able
to move to new hardware platforms, beyond the VAX, as
they became available. This, along with the availability
of source code, another Unix invention, sold DARPA on
Unix. DARPA began to fund the research effort of BSD,
and through this funding, BSD version 4.x (4BSD) became
the first Unix to offer the TCP protocol running on the new
Ethernet hardware, another interest of DARPA.
In September 1983, 4.2BSD was released officially, and
it included TCP/IP networking and the Berkeley Socket
interface. Sockets form the core of the Unix networking
implementation of TCP/IP, and allow different comput-
ers to publish “ports” to which other processes on other
computers can “bind,” allowing them to talk to one an-
other over the common Unix file abstraction via read()
and write(). This release is most significant because it de-
fined what Unix networking was to look like, as well as
fundamentally delivering on DARPAs commission. BSD’s
socket architecture has become a networking standard
and has been incorporated in most modern operating sys-
tems, including Microsoft Windows. The Berkeley socket
interface now forms the fundamental network connecti-
vity for all Internet traffic.BABEL: The Commercialization of Unix
In 1982, the Justice Department concluded its decades-
long dispute with AT&T by agreeing to a landmark agree-
ment: the dissolution of Western Electric entirely and the
divestiture of AT&T’s phone service into the now famously
independent “Baby Bells.” With the Baby Bells handling
the phone service, AT&T was now free to engage in busi-
ness activities entirely outside of its traditional albatross:
the pure delivery of phone service. This meant they could
begin to sell software, including Unix, a plan they put into
action immediately under the auspices of a new corpora-
tion called AT&T Information Systems.
This also meant that AT&T was considering its source
code to be intellectual property and had to protect its dis-
tribution, lest it lose its status as a trade secret (which,
ironically, it ultimately did). This meant that John Lions’s
wonderful commentaries on the Version 6 source code
(he had transcribed thousands of lines of pure source
in the commentaries) were now illegal, and their pub-
lication and distribution was banned. For decades, his
commentaries were photocopied over and over again anddistributed underground. Having in hand one of these
“original” photocopies is a prized possession among cur-
rent Unix cultural aficionados.
The net effect of the 1982 decree was that Unix became
a commercial entity, which resulted in a proliferation of
vendor-based Unix offerings. AT&T sold its own versions
that derived from Version 7, with corporate license prices
rising as high as $200,000 for a single source license by
1993 (Salus, 1994, p. 222).
By June 1982, work on 4.2BSD had already begun, and
Bill Joy saw the commercial writing on the wall and left
the CSRG at Berkeley to join with Andy Bechtolsheim,
who had designed a new workstation capable of running
4.2BSD. Their new company was called Sun Microsys-
tems, and their new workstation was dubbed the Sun
Workstation. Sun took the 4.2BSD core and began to sell
its own SunOS, based on 4.xBSD, on its workstations.
Other companies followed and entered the competitive
foray. IBM came out with AIX (AT&T flavor) for its work-
stations, Hewlett-Packard offered HP-UX (AT&T flavor),
Digital came out with ULTRIX and then later Digital Unix
(BSD flavor), and Silicon Graphics offered IRIX (AT&T
flavor). The list of commercial offerings exploded, with a
multitude of incompatible Unix systems and new licens-
ing costs.
The issues in licensing, pricing, and portability prom-
pted an exasperated reaction in the academic commu-
nity, used to a Unix tradition of open source access, and
this reaction prompted several significant results. The first
was a move by the Institute of Electrical and Electron-
ics Engineers (IEEE) to form a committee in 1986 to de-
fine a formal standard for Unix-based operating systems
to try and regain some compatibility. This standard was
called POSIX, which stands for Portable Operating Sys-
tems based on Unix.
The second result was an announcement by AT&T,
in 1987, to purchase some shares in Sun Microsystems,
which resulted in a powerful marriage between the BSD
and AT&T versions. The first major result of this new re-
lationship was the integration of SVR3 and 4BSD into a
new operating system offering from Sun called Solaris.
The second result was the creation of the Open Software
Foundation (OSF), a group formed by the “other” Unix
vendors, who did not want to be left out in the cold.
This group included Digital, IBM, and Hewlett-Packard
as heavy hitters, among others.
The commercialization of Unix, and the concomitant
cost of licenses and end of free source code, led to sev-
eral significant free alternatives. Foremost among these is
Richard Stallman’s creation of the Free Software Founda-
tion (FSF) in 1984. Stallman was working in MIT’s Arti-
ficial Intelligence Laboratory and was offended by all the
commercialization and licensing issues of the new propri-
etary Unix versions. The FSF is responsible for delivering
to the entire Unix community the Emacs editor, which
Stallman himself wrote, as well as a whole suite of tools
that were “free”—free not in the sense that they did not
cost money but that they werefreeto be shared, improved,
enhanced, everything provided with source code but never
to be commercialized. The software from Stallman’s FSF
was dubbed “GNU” software. GNU is a recursive acronym
meaning “Gnu’s Not Unix,” for Unix had become in