🚀 go-pugleaf

In article <13785@cbmvax.commodore.com>, valentin@cbmvax.commodore.com (Valentin Pepelea) writes:
> In article <35789@ut-emx.UUCP> lshaw@walt.cc.utexas.edu (logan shaw) writes:
>>
>>> Another problem is that even if you provide the possiblity for new
>>> applications to run protected within the environment, the fact that older
>>> programs can still jog around the address space and wreak havoc, defeats
>>> the initial purpose.
>>
>> But they can't wreak havoc with the memory declared as protected.  Granted,
>> it won't be 100% safe, but it will sure be alot better than it is right now.
>>
>> I was under the impression that (motorola, at least) MMU's worked by setting
>> certain memory pages with certain attributes (protected, etc), so the
>> programs which asked for protected memory would be protected from everything,
>> but older programs wouldn't be protected from newer programs.
> 
> Not quite. Protected tasks would still have their TCB in MEMF_PUBLIC memory,
> which by definition means "Go ahead, stomp on me!" Ditto for memory lists
> message ports, messages, I/O requests, etc. If you cannot provide 100% memory
> protection and recoverability, then you might as well not provide it at all.
>
 
 Don't see why. Other tasks don't have to write to it, they can go through the
system to do anything that has to be done to another task. The system allocates 
memory, so the memory lists can be protected. Message ports, well I use the
system to pass a message. If you don't, then whats it there for? Show? To take
up space in the ROM?
 
> You might disagree, but remember, I'm always right.  ;-)
> 

 A matter of opinion. (Not mine)

>> It can't be _that_ difficult to write.  PLEASE can we have this in 2.1?
>> Please, please, please? Pretty please with syntactic sugar on top of it?
> 
> As I have said before, the technical difficulties are not what is keeping us
> from coming out with incredibly useful enhancements. You have to factor in the
> energy constant, the resistance ratio and the friction coefficient. I found
> out the hard way.
> 
>> Just _once_ i'd like to see a requestor like this:
>> /---------------------------------------\
>> | CLI Process 2 tried to hose Process 3 |
>> |                                       |
>> | /--------\   /--------\     /-------\ |
>> | | Freeze |   | Ignore |     | Reset | |
>> | \--------/   \--------/     \-------/ |
>> \---------------------------------------/
> 
> Indeed, coming out with a fully memory protected operating system which
> protects even old software, but remains compatible by presenting one of these
> requesters every time an illegal access happens, is technically possible.
> But these requesters would pop up several times per second, and would leave
> novice users rather confused.

 Don't care about all old software, just the well behaved stuff. Misbehaved
software will soon be upgraded if they want it to be used.

> 
> Another option would be to come up with an operating system that provides
> full memory protection, but would allow the user to turn it on only optionally.
> Easy. But to evaluate the likelyhood of such a thing happening, you have to
> factory in the energy constant, the resistance ratio and the friction
> coefficient...
>

 Good. Do it. :)
 
> Valentin
> -- 
> The Goddess of democracy? "The tyrants     Name:    Valentin Pepelea
> may distroy a statue,  but they cannot     Phone:   (215) 431-9327
> kill a god."                               UseNet:  cbmvax!valentin@uunet.uu.net
>              - Ancient Chinese Proverb     Claimer: I not Commodore spokesman be

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