Minix, the miniature Unix from Andy Tanenbaum was initially released in 1987 for IBM PC and compatibles. In 1991 it was released for the Atari ST line of computers, in version 1.5, among ports for the Amiga, the 68k-based Macintosh, and the Sun Sparc. In 2000, it was relicensed in a bsd style license

Minix 1.x was meant to be system call compatible with Research Unix v7, which explains the small size of the distribution ( 8 MB including source code and C compiler ) and the lack of features. Minix 1.5 comes in two flavours, a floppy disk distribution containing the OS, C compiler and source code, and a bootable demo disk.

As an alternative you could try a recent FreeMint , which is a TOS compatible Unix Clone.

Hatari is a free ( as in free speech ) Atari ST emulator, which emulates quite well the original hardware, since it allows running third party operating systems besides Atari TOS. Runs on Unix-like systems.

The documentation for Minix 1.5 is available at http://minix1.woodhull.com/pub/refman.1.5/, in nroff format. To read it, you have to download the .nrf file along the macros file, and use the following command:

groff -man -Tascii Atari.nrf |sed -e 's/^             //'  |less -Rse

As an alternative it is possible to output a ps file

cp macros mini.tmac
groff -M $PWD -m minix  Atari.nrf   > Atari.ps

As groff has problem parsing the minix macros file, you could try with the classical Unix Troff from the Heirloom Project

• Download the floppy distribution from http://www.minix3.org/previous-versions/Atari in a directory
• Rename all the floppies images so that they have the .st file extension. Hatari need this to know it has to do deal with raw floppies images
• If need fix the keyboard layout on the boot disk in you have a non-QWERTY layout, using the documentation mentioned above
• Boot the virtual ST with

hatari --mono  --confirm-quit 0 disk01.st 

• Swap floppy disk02.st and disk03.st with Alt +D when asked, until you get your Minix prompt.

Hint: the user account ist ast with password Wachtwoord. The root password is indicated in the documentation mentioned above.

To save the burden of this heavy disk swapping, you can just save the state of the Virtual Machine with AltGr+K, and AltGr+L will load everything again the next time.

Man pages for Minix 1.5 on the PC are available from OldLinux (as Linux was initially developped from a Minix 1.5 system) You miss the documentation couple of Atari specfic command, but for the rest everything applies to ST Minix.

The ACSI hard drive emulated by Hatari is recognized by Minix as this test command ( in Minix ) works:

     dd  if=/dev/hd5  of=/dev/null  count=200
     200+0  records  in
     200+0  records  out

Serial port has not been tried yet.

Here is a a photo of Minix running on a Atari, displaying the /etc/rc init file :

The boot sequence can be seen in this youtube video.

Minimum requirements for running Minix on a real Atari are 1 MB RAM, and a 720k floppy disk drive. Use of a hard drive is optional ! The base system will run from three floppies (kernel, root, /usr ) in RAM. I used for myself the old Atari of my youth, a 520 STE expanded to 4 MB RAM, with a 20 MB Megafile hard drive bought on Ebay.

The floppy disks image shoud be then written with the Unix dd of the DOS/Windows Rawrite on Atari Compatible floppies, which means double side double density floppies.