[MiNT] CT60 and memory protection

[xavier.joubert@free.fr (Xavier Joubert)]

Hi all !

I'm one of the programmer in charge of the software for the CT60.

> > case. Ideas welcome. And also I would be for telling Rodolphe Czuba about
> > the PMMU cookie, so that perhaps the 060 TOS for the new 060 accelerator
> > board would use some manners when reprograming the PMMU.

?? My CT2b set a PMMU cookie and a _CT2 one.

> I discussed this with him, and he said that the CT60 won't use the PMMU like
> the CT2 does. There's only one bank of memory anyway, and it's physically
> mapped to the same location as TT-RAM.

In fact the PMMU is used as default when first booting the board. A PMMU
cookie is present to indicate this fact. This had to be done to maximize
performances with TOS (copying Flash and bottom of ST-RAM to TT-RAM.).

An option is present to deactivate PMMU use. In this mode, the PMMU
cookie is not set, and the MMU tree looks exactly the same as the
original Falcon Tree. Of course, because of differences between 030 and 060,
it consumes more than 1 Mbyte, instead of 256 bytes...

> Btw. he also said that MP *does* work on MiNT, even though it's perfectly
> clear that it doesn't. He obviously hasn't tried MiNT himself (in fact he
> called it "a pitty false OS with no memory protection" in a private
> discussion about a year ago) so I wouldn't expect him to consider MiNT at
> all when patching the new TOS.

We're trying our best to keep CT60 as compatible as possible with original
Falcon. We hope MiNT and Linux will boot directly without any modification.
If a problem arise, I will give you all support to correct this.

I'm very interrested in MiNT working on CT60, since I use 1.15.5. (I tried
1.15.10 but didn't manage to boot my KGMD. Looks like I need to upgrade my
Minix XFS.).

> However, the CT60 has a 512Kb flash-ROM and will be delivered with tools to
> write to the flash, so it shouldn't be impossible to fix any problems
> ourselves.

I think you will have a very good surprise with the well known software
license used on the CT60 project.


Regards,

Xavier Joubert