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From CP/M to TOS MiNT & MultiTOS MiNT goes FreeMiNT The XaAES story
MiNT -TOS goes Unix
Even on the models that followed the ST, Atari stayed with the approach to have TOS loaded from ROM. While TOS did progress in many ways it was still a singletasking OS. The AES in TOS was upgraded to handle 3d-objects, colour icons and much more, and the rest of the system also slowly got more modern and robust.
Eric Smith
Eric Smith
But while even the last computer to be produced by Atari (the Falcon 030, 1992) was shipped with a singletasking TOS stored in ROM, disk based solutions had started to appear.
Back in 1990 a Canadian programmer named Eric Smith had released the first version of a program called MiNT, which was a recursive acronym for "MiNT Is Not TOS". Eric had been working on a GNU C library for the ST, and porting GNU software. It soon turned out that porting software originally written for Unix to TOS was difficult since TOS lacked many of the features of Unix. It then occured to him that it might be easier to add the missing features to TOS rather than patching any Unix program that he wanted to port, and so MiNT was born.
The program's task was to replace larger parts of TOS with a system that could handle pre-emptive multitasking, but that was not all it did. Eric had designed it in a way very similiar to Unix, something that ensured that it would be easy to port Unix software from other hardware platforms to MiNT on Atari.
MiNT in the early days was however quite restricted to most end users as it would only allow text based programs (that did not address AES) to multitask, while still only 1 GEM application could run concurrently. But this limitation mostly resided within the AES, GEM. MiNT itself now offered a pre-emptive system that to a large extent provided a Unix compatible environment and at the same time maintained TOS compatibility. Thanks to releasing MiNT on the internet Eric got in touch with developers all over the world who wanted to help him develop MiNT further. Even Atari employees like Alan Pratt got involved and he actually was the one that added support for the Atari TT in MiNT.
TOS goes multitasking - Enter MultiTOS
In the early 90's Atari had realized that multitasking was a necessity for the future and started looking for ways to turn TOS into a multitasking OS. As Alan Pratt was already familiar with MiNT he suggested that it should be used as a base for the new operating system.
MultiTOS installation disk
While not supposed to replace TOS entirely, MiNT would constitute the kernel of the new OS. In preparation for an official release a lot of things were restructured inside MiNT and memory protection was being added. When Alan Pratt suddenly left Atari, Eric himself was hired to finish the kernel. To manage a multitasking environment Atari also had to develop a replacement for the AES that was not limited to running only 1 application at a time. The new OS thus consisted of MiNT and AES 4.0, and the bundle was called MultiTOS. The MiNT acronym now also was changed into "MiNT Is Now TOS". MultiTOS was released in early 1993 and while finally offering Atari users a multitasking system it also had some serious drawbacks - the system was very slow.
No more TOS
Sadly enough, it would turn out that MultiTOS was the last version of TOS ever to be released by Atari. Internally they did release a beta version of the long awaited TOS 5.0 which still was a singletasking OS but with some preparations made for going fully multitasking. This beta version contained AES 4.1 and was named TOS 4.92, and while it managed to leak out to some FTP-servers it was naturally not aimed at end users and those who tried it quickly discovered that it was quite buggy and unstable. An updated version of the multitasking GEM replacement in MultiTOS (While also named AES 4.1 it was a newer verison of AES than the one distributed with TOS 4.92) was also distibuted to developers, but then things came to an abrupt ending.
In the efforts to focus all their resources on the game console Atari Jaguar, Atari had decided to drop all development and support for their computer line. If this would have happened a few years earlier the saga of TOS might have ended here, but 2 things prevented this from happening. Eric managed to convince his superiors to release the Atari version of MiNT under a less restrictive license, something that made it possible for anyone interested to redistribute their own versions of the OS. Furthermore, MiNT had appeared at a time when internet had started to gain popularity and this had already created a strong MiNT community - the internet provided excellent conditions for coordinating open source developments.
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