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Unformatted text preview: used on a wide variety of
systems, it is especially prevalent on RISC workstations such as those from Sun
Mircosystems, Hewlett-Packard, IBM, and Silicon Graphics.
Development of Unix
Unix was developed in the early 1970s at Bell Laboratories by Ken Thompson and
Dennis Ritchie for a small PDP-11 computer. It was the first operating system to
be written in a high-level language C. The normal practice till then was to use
assembly language for writing operating systems due to which operating systems
were system dependent. That is, they were usable only on the system for which
they were developed. However, since Unix was written in C language, moving it
to a new machine, known as porting it, was much easier. This was an important
reason for its large popularity and availability on a wide variety of systems.
BSD Unix and Other Unix Versions
The ease with which Unix could be modified led to the initiation of Unix-based
development activities at many universities and research laboratories. The most influential of the non-AT&T development groups was the group at the University
of California at Berkeley. This group ported Unix to the VAX computer and
produced the Berkeley Software Distributions (BSD) versions of Unix. Among the
improvements made by this group in t original Unix version, the notable ones were
support for virtual memory, demand paging, a new shell (called csh), and the
TCP/IP network protocols. BSD version also added several OS capability
enhancement software to Unix, including a new text editor (called vi editor),
Pascal and Lisp compilers, and many more.
Over the years, as Unix grew in popularity, many computer vendors have ported it
on their systems and have enhanced and maintained their own versions of Unix.
This has resulted in the creation of a wide variety of Unix, and Unix-like operating
systems. For example, Unix supported on IBM systems is called AIX, Unix
supported systems supplied by Sun Microsystems is called Solaris, Unix supported
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This document was uploaded on 04/07/2014.
- Spring '14