<P> The introduction of the Intel 80386 CPU chip in October 1985, with 32 - bit architecture and paging capabilities, provided personal computers with the ability to run multitasking operating systems like those of earlier minicomputers and mainframes . Microsoft responded to this progress by hiring Dave Cutler, who had developed the VMS operating system for Digital Equipment Corporation . He would lead the development of the Windows NT operating system, which continues to serve as the basis for Microsoft's operating systems line . Steve Jobs, a co-founder of Apple Inc., started NeXT Computer Inc., which developed the NEXTSTEP operating system . NEXTSTEP would later be acquired by Apple Inc. and used, along with code from FreeBSD as the core of Mac OS X (macOS after latest name change). </P> <P> The GNU Project was started by activist and programmer Richard Stallman with the goal of creating a complete free software replacement to the proprietary UNIX operating system . While the project was highly successful in duplicating the functionality of various parts of UNIX, development of the GNU Hurd kernel proved to be unproductive . In 1991, Finnish computer science student Linus Torvalds, with cooperation from volunteers collaborating over the Internet, 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 . Since then, the combination of the two major components has usually been referred to as simply "Linux" by the software industry, a naming convention that Stallman and the Free Software Foundation remain opposed to, preferring the name GNU / Linux . The Berkeley Software Distribution, known as BSD, is the UNIX derivative distributed by the University of California, Berkeley, starting in the 1970s . Freely distributed and ported to many minicomputers, it eventually also gained a following for use on PCs, mainly as FreeBSD, NetBSD and OpenBSD . </P> <P> Unix was originally written in assembly language . Ken Thompson wrote B, mainly based on BCPL, based on his experience in the MULTICS project . B was replaced by C, and Unix, rewritten in C, developed into a large, complex family of inter-related operating systems which have been influential in every modern operating system (see History). </P> <P> The Unix - like family is a diverse group of operating systems, with several major sub-categories including System V, BSD, and Linux . The name "UNIX" is a trademark of The Open Group which licenses it for use with any operating system that has been shown to conform to their definitions . "UNIX - like" is commonly used to refer to the large set of operating systems which resemble the original UNIX . </P>

What are the various types of operating system