What is memory protection and why is it so hard to implement for the AmigaOS?

[HammerD]

So if they drop backward compatibility and decide to re-do the kernel then they can include memory protection right!? Or there is something in the AmigaOS philosophy that still makes this a hard task to achieve?

Well there was as chance with both MorphOS and OS 4.0 to  make a clean break and sandbox 3.X apps, and make new API's and basically start over fresh.

Both approaches didn't do that, however, probably to maintain backwards compatibility within the older applications.   Plus, defining all new API's is basically re-writing everything from scratch.  Maybe that was too much work given the available budgets and resources.

If it was me, and I had unlimited resources and time, I would sandbox legacy apps and start with a clean slate, adding features like SMP, etc.

[HammerD]

If Apple can move from OS9 to OSX with compatiblity for OS9 applications (IIRC, it is in an emulation layer, but compatible none the less,) then...

From the wiki page on the history of MacOS X:

http://en.wikipedia.org/wiki/History_of_Mac_OS#Mac_OS_X

"...This is a compatibility layer in Mac OS X (in fact a Mac OS X application, originally codenamed the "blue box") that runs a complete Mac OS 9 operating system, so allowing applications that have not been ported to Carbon to run on Mac OS X. This is reasonably seamless, though "classic" applications retain their original Mac OS 8/9 appearance and do not gain the Mac OS X "Aqua" appearance."


So, it looks like they basically sandboxed older apps, and in fact the entire OS 9 to run on top of MacOS X.  Sort of like runnine E-UAE now on OS4, or WinUAE on Windows, although they made it appear more seamless, I think.

[HammerD]

@outlawl2

Well there are more than 2 "camps" if you wish to use that terminology

1) Classic users
2) OS4 users
3) MorphOS users
4) AROS users
5) Emulation users (amithlon/winuae)
6) Other (users of minimig, NatAmi), sort of classic users

Of course, many people are a mix of some or all of the above

[HammerD]

I think many users wanted backwards compatibility, thus you see the limitations on the modern incarnations of OS 3.x today.  Done that way probably because it would have taken too much resources to do it the way Apple did.