Author Topic: Running Amiga/AROS on modified NetBSD kernel  (Read 340 times)

PurpleMelbourne

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Running Amiga/AROS on modified NetBSD kernel
« on: December 14, 2018, 05:19:02 PM »
Kickstart doesn't have networking built into it. Also no memory protection. NetBSD has both of those things.

I'm wondering what would need to be modified to make a NetBSD kernel to become Amiga system call compatible.

And then the same thing for a NetBSD kernel on Atari. As I'm wondering what it would take for an Atari to run AROS. Vampire will give Atari the Amiga custom chips. So it will be  strange, Draco like Amiga which wants to be able to run Atari software.

They have memory protection with their newer OS's. But the Amiga GUI would be a big improvement for them, and if they could soon run Amiga software then it would expand the community. So I''m wondering what it will take to create Atari compatibility, and the foundations its build upon. Memory protection and Networking in the kernel (Kickstart).

Samurai_Crow

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Re: Running Amiga/AROS on modified NetBSD kernel
« Reply #1 on: December 14, 2018, 07:34:43 PM »
The memory protection on NetBSD requires an old 68040-style MMU.  The 68080 MMU is not backward compatible.  The Vampire would need a total rewrite of either Linux or NetBSD kernel to use the 68080 MMU.  New versions of AROS that don't need to worry about backward compatibility have MMU support for other systems but not for the Vampire yet.

The 68080 MMU has a minimum page size of 128KB.  The 68040 MMU has a maximum page size of 8k.  The 68080 has an additional unit for memory protection called the MPU (memory protection unit).  The MPU is pageless and instead is byte-addressable for tighter granularity than a traditional MMU offers.

Why not concentrate on making a 68080 enhanced native AROS with memory protection?

Fats

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Re: Running Amiga/AROS on modified NetBSD kernel
« Reply #2 on: December 14, 2018, 07:41:41 PM »
Kickstart doesn't have networking built into it. Also no memory protection. NetBSD has both of those things.

I'm wondering what would need to be modified to make a NetBSD kernel to become Amiga system call compatible.

It's not possible to force memory protection with separate memory spaces on existing Amiga programs. These makes assumptions they can write in each other's memory and will crash if you don't allow it anymore.

PurpleMelbourne

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Re: Running Amiga/AROS on modified NetBSD kernel
« Reply #3 on: December 16, 2018, 07:55:58 PM »
I've noticed a thread where they were trying to compile some BCPL code in the leaked Amiga OS3.1 source. I don't know the specific files, but I presume they are Kickstart, and according to one of the Apollo guys, the Amiga cannot be portable without those files being ported.

I wonder if the Draco has some more recent code of this, or perhaps shares the original as well. But either way, if we can get past all the legacy code and onto a FOSS foundation then we shall be in a more secure position :-)

http://eab.abime.net/showthread.php?t=89449