Wikipedia: Minix

Minix was a commercial stripped down version of unix that ran on IBM PC and [IBM PC/AT]?computers in the late 1980s and early 1990s. Later versions ran on 68000? based machines (such as the Atari ST and early Apple Macintosh) and SPARC? based machines (such as [Sun workstation]?s).

Linux was influenced by Minix.

Minix was written by [Andrew S. Tannenbaum]? from Vrije Universiteit, Amsterdam, The Netherlands as an appendix or example in the book "Operating Systems: Design and Implementation" (ISBN 0-13-637331-3 (amazon.com, search)). The whole 12000 lines of source code of the kernel, memory manager, and file system is printed in the book; it is mostly written in C.

Minix distributions has the following ISBN numbers. They all contain all the source:

A set of disks for IBM PC with 640K RAM - ISBN 0-13-583873-8 (amazon.com, search). Can be used with 512K computers if you adjust some program sizes.
A set of disks for IBM PC with 256K RAM - ISBN 0-13-583881-9 (amazon.com, search). Does not include the C compiler since it is not runnable.
A set of disks for IBM PC/AT with at least 512K RAM. ISBN 0-13-583865-7 (amazon.com, search). 1.2M diskettes are used instead of 360K diskettes.
Nine-track, industry standard 1600 bpi magnetic tape in UNIX "tar" format. ISBN 0-13-583899-1 (amazon.com, search). Includes an IBM PC simulator and some libraries and programs that make it possible to run the MINIX file system on a VAX or other minicomputer running UNIX.

There is also a file system called Minix. This is the default file system type used when installing Minix. It is also used by some Linux distributions as the format for bootable disks or other situations where a low-overhead filesystem is needed.