MINIX is a Unix-like computer operating system based on a microkernel architecture. Andrew S. Tanenbaum wrote the operating system to be used for educational purposes; MINIX also inspired the creation of the Linux kernel. Its name derives from the words minimal and Unix. Released under the BSD license, MINIX is free and open source software.
Andrew S. Tanenbaum created MINIX at Vrije Universiteit in Amsterdam to exemplify the principles conveyed in his textbook, Operating Systems Design and Implementation (1987). An abridged 12,000 lines of the mainly C source code of the kernel, memory manager, and file system of MINIX 1.0 are printed in the book. Prentice-Hall also released MINIX source code and binaries on floppy disk with a reference manual. MINIX 1 was system-call compatible with Seventh Edition Unix.
Tanenbaum originally developed MINIX for compatibility with the IBM PC and IBM PC/AT microcomputers available at the time. MINIX 1.5, released in 1991, included support for MicroChannel IBM PS/2 systems and was also ported to the Motorola 68000 and SPARC architectures, supporting the Atari ST, Commodore Amiga, Apple Macintosh and Sun SPARCstation computer platforms. There were also unofficial ports to Intel 386 PC compatibles (in 32-bit protected mode), National Semiconductor NS32532, ARM and INMOS transputer processors. Meiko Scientific used an early version of MINIX as the basis for the MeikOS operating system for its transputer-based Computing Surface parallel computers. A version of MINIX running as a user process under SunOS was also available.
Demand for the 68k-based architectures waned, however, and MINIX 2.0, released in 1997, was only available for the x86 and Solaris-hosted SPARC architectures. It was the subject of the second edition of Tanenbaum’s textbook, co-written with Albert Woodhull and was distributed on a CD-ROM included with the book. MINIX 2.0 added POSIX.1 compliance, support for 386 and later processors in 32-bit mode and replaced the Amoeba network protocols included in MINIX 1.5 with a TCP/IP stack. Unofficial ports of MINIX 2.0.2 to the 68020-based ISICAD Prisma 700 workstation and the Hitachi SH3-based HP Jornada 680/690 PDA were also developed.
Minix-vmd is a variant of MINIX 2 for Intel IA-32-compatible processors, created by two Vrije Universiteit researchers, which adds virtual memory and support for the X Window System.
The design principles Tanenbaum applied to MINIX famously influenced the design decisions Linus Torvalds applied in the creation of the Linux kernel. Torvalds used and appreciated MINIX, but his design deviated from the MINIX architecture in significant ways, most notably by employing a monolithic kernel instead of a microkernel. This was famously disapproved of by Tanenbaum in the Tanenbaum-Torvalds debate. (Tanenbaum explained again his rationale for using a microkernel in May 2006.) Early Linux kernel development was done on a MINIX host system, which led to Linux inheriting various features from MINIX, such as the MINIX disk filesystem format.
(Grabbed from Wikipedia)