Memory protection...

Virtual Cowboy

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May 12, 1997, 3:00:00 AM5/12/97

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is there a good programmer out there who wants to write a memory-protection
patch... ? That lets me remove crashed tasks like in (ARHG, &/(%ง) Windoze...
C'ya
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Christian Stieber

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May 13, 1997, 3:00:00 AM5/13/97

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Virtual Cowboy (vic...@ibm.net) wrote:
> is there a good programmer out there who wants to write a memory-protection
> patch... ? That lets me remove crashed tasks

It's not possible if you want to keep 100% compatability with
existing applications, and not easily implemented by just patching
some functions.

-> This should be left to the people working on AmigaOS (if any), or
the ones working on a replacement.

Christian

Mike Redrobe

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May 13, 1997, 3:00:00 AM5/13/97

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Hi, Virtual Cowboy , on 12-May-97 21:00:30 you scribbled....
VC> is there a good programmer out there who wants to write a
VC> memory-protection patch... ? That lets me remove crashed tasks like in
VC> (ARHG, &/(%ง) Windoze... C'ya

"memory protection patch" -not possible

but you can get similar functionality with enforcer (needs mmu) or MCP
and something like sysinspector(to remove task,windows,screens allocated)

now if we could tie these together you'd get something nice or something
horrible ;)

Mike

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Juergen Fischer

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May 14, 1997, 3:00:00 AM5/14/97

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<5l9hel$b...@squire.cen.brad.ac.uk>... LA GUEST (lag...@comp.brad.ac.uk) wrote:
>
> : is there a good programmer out there who wants to write a memory-protection
> : patch... ? That lets me remove crashed tasks like in (ARHG, &/(%ง) Windoze...
> : C'ya
>
> Many people say that it isn't possible to implement MP/VM on the Amiga without breaking lots of applications.
>
at least you could protect unallocated memory. would detect buggy software
quite easy. its no real protection, but programmers writing software with
that kind of protection would deliver less buggy software.

and yes, a kill instruction would be handy!
is there maybe a handy too out there where I get a list of all tasks
to select the one I want to kill ?

--- fisc...@Informatik.TU-Muenchen.DE (Juergen "Rally" Fischer) =:) ---

Eka Durmin

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May 14, 1997, 3:00:00 AM5/14/97

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LA GUEST <lag...@comp.brad.ac.uk> wrote:
> : is there a good programmer out there who wants to write a memory-protection
> : patch... ? That lets me remove crashed tasks like in (ARHG, &/(%ง) Windoze...
> : C'ya

> Many people say that it isn't possible to implement MP/VM on the Amiga without breaking lots of applications.

I use VMM for Virtual Memory... and it works fine!

It would be very very nice if there is a program wich can do MP.

Regards,
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Christian Stieber

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May 14, 1997, 3:00:00 AM5/14/97

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Juergen Fischer (fisc...@Informatik.TU-Muenchen.DE) wrote:

> at least you could protect unallocated memory.

Very difficult. Amiga programs don't care about page sizes, so how
do you protect half a page?

> is there maybe a handy too out there where I get a list of all tasks
> to select the one I want to kill ?

Verz dangerous. If the program you want to kill has outstanding
messages, is waiting for signals or other things, killing it
will trash memory (best case) when any of these events happen,
and the OS tries to signal/restart a non-existing task.

Now, why do you want to kill a program, anyway? You'll have to
reboot anyway, since a) you don't know what the program has done
to the system, and b) killing it won't free allocated resources.

Christian

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Kyzer

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May 14, 1997, 3:00:00 AM5/14/97

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When Juergen Fischer met comp.sys.amiga.programmer....:
: and yes, a kill instruction would be handy!
: is there maybe a handy too out there where I get a list of all tasks

: to select the one I want to kill ?

There's plenty, but the problem is not killing the task (no problem there)
but freeing the resources it allocated when it was running, and killing it's
childtasks, things like that. This is why we need Resource Tracking more than
MP or VM, folks! It's much easier to implement, also.

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Wez Furlong

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May 14, 1997, 3:00:00 AM5/14/97

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On 14 May 1997 18:48:34 GMT, Kyzer <junk...@sysc.abdn.ac.uk> wrote:
: There's plenty, but the problem is not killing the task (no problem there)

: but freeing the resources it allocated when it was running, and killing it's
: childtasks, things like that. This is why we need Resource Tracking more than
: MP or VM, folks! It's much easier to implement, also.

The Kill from muFS does some trickery to try and shut down windows and
screens etc. but obviously can't free up any memory alloc'ed by the
program itself, since this isn't pointed to by the Task* or Process*
pointers -- how about rewriting malloc (and similar functions) to use
the MemList pointer in the Task structure? We would be one step nearer
resource tracking...

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Hans Guijt

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May 14, 1997, 3:00:00 AM5/14/97

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Juergen Fischer (fisc...@Informatik.TU-Muenchen.DE) wrote:
>and yes, a kill instruction would be handy!
>is there maybe a handy too out there where I get a list of all tasks
>to select the one I want to kill ?

ARTM, aka Amiga Real Time Monitor. Lets you kill and tinker with system
objects as much as you want.

Hans

Christian Stieber

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May 15, 1997, 3:00:00 AM5/15/97

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Wez Furlong (wjf...@york.ac.uk) wrote:

> pointers -- how about rewriting malloc (and similar functions) to use
> the MemList pointer in the Task structure? We would be one step nearer
> resource tracking...

This will break existing programs, too --- it is perfectly okay to
allocate memory from one task, terminate that task, and free the
memory from another task.

Christian

Martin Recktenwald

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May 15, 1997, 3:00:00 AM5/15/97

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In comp.sys.amiga.programmer Wez Furlong <wjf...@york.ac.uk> wrote:
> pointers -- how about rewriting malloc (and similar functions) to use

^^^^^^
There is no such function in the AmigaOS.
You're probably talking about AllocMem() & Co.

> the MemList pointer in the Task structure? We would be one step nearer
> resource tracking...

Only 1000 more miles to go ...

Martin.
-------------------------------------------------- mre...@cscip.uni-sb.de

Rask Ingemann Lambertsen

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May 15, 1997, 3:00:00 AM5/15/97

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On 13-Maj-97 10:57:02, Christian Stieber wrote the following about "Re: Memory
protection...":

> Virtual Cowboy (vic...@ibm.net) wrote:
>> is there a good programmer out there who wants to write a memory-protection
>> patch... ? That lets me remove crashed tasks

> It's not possible if you want to keep 100% compatability with
> existing applications,

But the whole point of memory protection is that you _don't_ want to stay
100% compatible with existing applications ;-)

Seriously, obviously the broken programmes will break. As long as the
programmes that play by the OS rules still work, fine.

Regards,

Martin Recktenwald

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May 16, 1997, 3:00:00 AM5/16/97

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In comp.sys.amiga.programmer Wez Furlong <wjf...@york.ac.uk> wrote:

> Hmmm, why don't we rewrite the OS?.... :-)

What do you think is AROS? :-)

> IIRC, the AROS team have implemented memory protection fairly recently,

Your're mixing something up here. Ressource tracking is partially
implemented. No MP yet. To many open questions ...

> its a shame that they haven't got a full replacement for all of the OS
> yet. *sigh*

You're welcome to join the AROS team and write what you're missing :-)

Martin.
-------------------------------------------------- mre...@cscip.uni-sb.de

Wez Furlong

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May 17, 1997, 3:00:00 AM5/17/97

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On 16 May 1997 13:24:17 GMT, Martin Recktenwald
<mre...@kap03.cscip.uni-sb.de> wrote:
: In comp.sys.amiga.programmer Wez Furlong <wjf...@york.ac.uk> wrote:
: > its a shame that they haven't got a full replacement for all of the OS

: > yet. *sigh*
:
: You're welcome to join the AROS team and write what you're missing :-)

If I had the time (and a magic supply of money)... :-)

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URL : http://www.twinklestar.demon.co.uk/

Insult Of The Day: Thou lumpish tardy-gaited flirt-gill!

Kyzer

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May 18, 1997, 3:00:00 AM5/18/97

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Hans Guijt of hgu...@inter.nl.net wrote in comp.sys.amiga.programmer:

And then lock up and kill the computer 20 minutes later when you LEAST EXPECT
IT! :)

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Marc 'Nepomuk' Heuler

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May 19, 1997, 3:00:00 AM5/19/97

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In article <5l9acu$o...@sunsystem5.informatik.tu-muenchen.de>, Christian Stieber writes:

> Virtual Cowboy (vic...@ibm.net) wrote:
> > is there a good programmer out there who wants to write a memory-protection
> > patch... ? That lets me remove crashed tasks
>
> It's not possible if you want to keep 100% compatability with

> existing applications, and not easily implemented by just patching
> some functions.

I think it is possible, when 98% compatibility and <75% protection are
enough. Just develop a cooperative memprot library. Then supply the users
with system patches to make old apps use the library for most of their
memory. High compatibility can be reached by restricting usage to known
apps, much like GIGAMEM does it.

New apps can directly interface to the library, having identified
themselves beforehand to the patch system.

100% users install the library system only (no patches) and get 100%
compatibility in return for most (but not all) benefits.

Christian Stieber

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May 20, 1997, 3:00:00 AM5/20/97

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Rask Ingemann Lambertsen (ra...@kampsax.dtu.dk) wrote:

> > It's not possible if you want to keep 100% compatability with
> > existing applications,
>

> But the whole point of memory protection is that you _don't_ want to stay
> 100% compatible with existing applications ;-)
>
> Seriously, obviously the broken programmes will break. As long as the
> programmes that play by the OS rules still work, fine.

OS rules don't cazre about memory protection -> broken programs will
no longer work. Many non-broken programs will no longer work.