Minix-ST was the version of the Minix operating system for the Atari ST computers. I used it intensively during the early nineties. It was the Unix-like system I had at home, before switching to FreeBSD when I finally bought a PC. I still maintain a cross-compiler for Minix-ST based on modern versions of GCC, see my Minix-ST Cross-Development page.
The Atari ST was a Motorola M68000 based personal computer, introduced in 1985, quite affordable and for some reason especially popular in Germany, though it also was not unseen in certain circles here in the Netherlands.
The model that probably sold best was the Atari 1040 ST. It had an 8 MHz M68000 CPU and came with a full Mbyte of RAM, which was quite a lot in those days. And even better: you could actually address all that memory from your programs, in sharp contrast with the PC's of those days, where you had to live with 64 Kbyte segments. This and the fact that the M68000 CPU was so similar to what we used at work in our Unix boxes and workstations, made the Atari ST quite popular amongst technical and scientific users like me.
The Atari ST came with a graphical user interface called GEM, which was quite usable, although it was really a lot of work to write even moderately complex programs for it. What was really missing was a multi-tasking and tool-rich environment like Unix.
That environment became available with the introduction of Minix-ST in 1988, though we had to give up the GUI, since Minix completely replaced the native OS.
As you probably know, Minix was developed by Andy Tanenbaum for the IBM PC and compatibles and introduced in 1987. It was a Unix V7 look-alike intended for teaching OS classes and while certainly not free, it came with (almost) full source code and an accompanying text book was available that described the code in detail.
The porting of Minix to the Atari ST was definitely not trivial. Since the ST only had a very primitive MMU, it offered no relocation and no protection. To counter the lack of relocation, especially noticeable when doing a fork(), a mechanism called shadowing was devised. It was not a very fast solution, but it worked well enough for many usage patterns. The lack of protection was something we just had to live with. The idea back then was that on a personal machine you could only hurt yourself. Of course, that was before networking became widespread on personal computers.
The first version of Minix for the Atari ST as introduced in the fall of 1988 was 1.1 and as I remember it was equivalent to the Minix PC version 1.3. It was sold by Prentice-Hall and came on a set of diskettes accompanied by a booklet that explained the ST specific details. I recently found back the whole original set of 9 diskettes and you can download an archive containing the 360K disk images here.
Istvan Ostrosits went through the trouble of extracting the Minix-ST 1.1 source code from these diskette images into this separate archive and kindly shared the result.
In 1990 an update, Minix 1.5, was released with versions for the PC (and compatibles) and the Atari ST, but also for the Commodore Amiga and the Apple MacIntosh. This release came with a binder containing a quite complete manual and 10 diskettes.
Minix 1.5 was the last release that was sold by Prentice Hall separately from the text book. It originally came with a quite restrictive license. Later editions of the text book contained a CD-ROM with the software and the license was changed to a BSD like license. The license was also changed retroactively for the older versions (see here for more details), so you may now download the install disks for the different versions of Minix 1.5 from several locations (e.g. here on the official Minix3 site.)
For the PC version the sources of the OS and the commands are also available as tar.gz files, without the need to decipher the installation images. As far as I know, the sources for Minix-ST 1.5 were never available in that form, but can now be downloaded here. This is the complete source code for the OS, libraries, commands and the Atari specific utilities, as distributed on the original diskettes.
After Minix 2.0 appeared, there occasionally were discussions on Usenet newsgroups about doing a port of it to the Atari ST and other M68K platforms, but not much came of it, although George Harvey managed to do an unofficial port of Minix 2.0.2 to a 68020 based workstation, including networking (see here, if unavailable see the archived copy.)
Only quite recently a discussion appeared at the Atari Forum, where a person with the nick "tritonus" claimed to have Minix 2.0.2 and 2.0.4 running on the Atari ST, including networking. As a follow-up a complete disk image was posted here, including instructions how to use it with the Hatari 1.9 emulator. Since the Hatari 1.9 port did not even build on my FreeBSD system, I did not have the opportunity to try it and the source code is (sadly) not published separately. Nevertheless it looks quite interesting and I will certainly attempt to isolate the source code.
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