1. History of Network Operating Systems
Birth of Networks
The concept of data communications between computers began in the late 1960s and early 1970s,
when researchers began developing a way of connecting computers and exchanging information by way
of packets of data. Soon, the concept of a local area network (LAN) took hold, replacing the previous
model of a central computing node and so-called "dumb" terminals connected to it, as in IBM's
proprietary Systems Network Architecture (SNA) model. The development later on of TCP/IP
(Transmission Control Protocol/Internet Protocol) and Ethernet fostered the networking concept even
further. The need soon came for operating systems to not only deal with the inter-connectivity of the
networks but also the security aspect, according to a research paper from the American University
Computing History Museum.
Arrival of UNIX
During this period, several operating systems were developed, like IBM's MVS operating system, which
still dealt with SNA. However, the development of another operating system, dubbed UNIX, really paved
the way for NOS everywhere. After a project to develop a large and complex system called Multics failed
to get off the ground at Bell Labs in 1969, a group of Bell researchers, led by Ken Thompson and Dennis
Ritchie, started work on a less ambitious but no less powerful computing system.
After a rocky first few years, Ritchie developed the C programming language, which allowed UNIX to
become the first "portable" operating system, meaning it could be implemented on any computer
system. The relative simplicity of the system's design and the availability of its source code turned UNIX
into a darling of the academic world and a fixture on many university computer networks. Many
versions of UNIX were developed, but the Berkeley Software Distribution (BSD) version, developed in
University of California-Berkeley, became arguably the most popular, according to communications
powerhouse Alcatel-Lucent.
Netware Makes a Splash
The 1970s also saw the rise of microchips, which ushered in the era of microcomputers and the use of
personal computers in the consumer market. Alongside this revolution, a company called Novell became
a pioneer in network operating systems with the release of its Netware S-Net device. The product
essentially turned the IBM XT, a popular PC at the time that featured a hard drive, into a file-sharing

2. system on which workstations attached to the server in a star-like configuration (hence the "S-Net"
name).
Novell also developed its own NOS, also named Netware, for the device. By this time, several
competitors came up with their own NOS, but they were all proprietary and only ran on their receptive
hardware. In addition, these NOS were built on top of DOS (disk operating system), which was present in
practically every IBM PC at that time but was also a single-user, single-tasking system.
Because of its non-DOS-based, multitasking characteristics, as well as Novell's willingness to port its
system to a variety of different hardware, Netware soon became the operating system of choice on
every major LAN card, according to the Raj Rajagopal's book "Multi-Operating System Networking: Living
with Unix, Netware and NT."
The Next Generation of UNIX
Meanwhile, UNIX continued transforming the computer landscape, like when a BSD UNIX computer
severed the restrictions of ARPANET, which linked military and university sites, and planted the seeds of
what we now know as the Internet. Then in the mid-1980s, a company called Sun Microsystems took
UNIX and significantly enhanced its capabilities. The result, dubbed SunOS, added a graphical user
interface or GUI, made popular by the introduction of Mac OS and then Windows 3.1 into the consumer
market, as well as other features. Solaris, a newer version of SunOS, became even more popular among
network administrators.
Microsoft and IBM Team Up
As Novell secured its dominance of the LAN operating system market at that time through its Netware
NOS, a company named Microsoft tried to get a feel of where things were going. Early versions of its
DOS system featured some network-oriented features, while its MSnet product got the backing of
Novell competitors like 3Com, yet to no avail. Incursions into other operating systems such as early
versions of Windows were also met with user apathy.
Meanwhile, former minicomputer giant IBM had been seemingly left behind by the LAN revolution and
struggled to keep up with Novell. This prompted Microsoft and IBM to team up and develop OS/2, a
highly hyped operating system deemed as "the future of personal computing," according to Rajagopal's
book. Both companies put all their efforts into dethroning Netware with OS/2, placing it as a priority
even over other Microsoft projects like its stumbling Windows system. But with the release of Windows

3. version 3, Microsoft hit the jackpot. As millions of copies of Windows were sold, the industry dynamics
changed overnight and plans for OS/2 were forestalled.
Current Players
Nowadays, the major players in the NOS market include Windows, Netware (currently at Version 6.5),
and Cisco IOS (stands for "Internetwork Operating System"), as well as UNIX-based operating systems
like Linux or one of the many flavors of BSD UNIX.