I think you mean MINIX (MINimal UnIX)
It was developed as sample source code to teach operating systems by Andrew Tanenbaum of Vrije University, Amsterdam, The Netherlands, Minix was first introduced in 1987 in the book, "Operating Systems, Design and Implementation." Within a few months, more than 40,000 people subscribed to the Minix newsgroup on the Internet.
There were versions for the PC, Mac, Sun, Amiga and Atari ST.
More information at www.minix3.org.