After the 60’s the most of the calculators were made by IC and the performances were better than the old generation systems. The main issue was the difficulty to transfer the technology to the common people for two reasons: the high cost of the integrated electronic components and the cost of the software to be installed. The most of the calculators were only “enterprise calculators” and the “home computers” were produced only between the 70’s and 80’s. In the 80’s Andrew Stuart Tanenbaum, an American professor of computer science at the Vrije Universiteit van Amsterdam, understood the modern home computers needed a minimal and multitasking operating system.
He designed the microkernel of MINIX (Minimal Unix) for educational purpose, then the first edition of it was released under a FREE BSD license (Not open source nor totally free). Different OS editions followed and different license editions, the 3d edition was released under a commercial BSD license. Tanenbaum described the architecture of MINIX 3.0 and the source code in a book of him: “ Operating Systems Design and Implementation- 3/E”.
The software architecture is made by 4 layers: the kernel, the device drivers, the server processes, the user processes. MINIX was originally designed for IBM PC/AT, IBM PC, Atari ST, Motorola 68000, Commodore Amiga, Sparc Station, Apple Macintosh. In the last version it is released for x86 and in phase of development for embedded processors such as: Power Pc, ARM7. The MINIX mascot is a Raccoon.