Operating Systems

Operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs.

Unix

Unix was originally written in assembly language then rewritten in C, developed into a large, complex family of inter-related operating systems which have been influential in every modern operating system.

“Unix-like” is commonly used to refer to the large set of operating systems which resemble the original UNIX.

“Unix-like” systems run on a wide variety of computer architectures. They are used heavily for servers in business, as well as workstations in academic and engineering environments. Free UNIX variants, such as Linux and BSD are popular in these areas.

MAC OS

MAC OS is a line of open core graphical operating systems developed, marketed and sold by Apple. MAC OS is a Unix-like operating system built on technology that had been developed at NeXT.

Steve Jobs, a co-founder of Apple, started NeXT, which developed NEXTSTEP operating system. NEXTSTEP would later be acquired by Apple and used along with code from BSD as the core of MAC OS.

Linux

Linux is Unix-like, but was developed without any Unix code.

GNU Project, started by Richard Stallman, was highly successful in duplicating the functionality of various parts of UNIX  but development of GNU Hurd kernel proved to be unproductive. In 1991, Linus Torvalds released the first version of the Linux kernel. It was soon merged with the GNU user space components and system software to form a complete operating system.

The main characteristic is that the software is free. Since the source code has been released to the public, and redistribution and changes can be freely performed, a great number of people around the world have participated to make Linux a better OS. As a background factor, it should not be forgotten that the Internet expansion that enabled people around the world to communicate with each other allowed this participation.

The Linux kernel is used in some popular distributions, such as Red Hat, Debian, Ubuntu and Google’s Android.

Microsoft Windows

Microsoft Windows is a family of operating systems designed by Microsoft and primarily targeted to Intel architecture based computers.

Windows’ usage on servers is not as widespread as on personal computers as Windows competes against Linux for server market share.