Hi all,
I've got a Sam, and my main beef with it is reliability, and I wonder if there is anything I can do to improve the situation? I think the problem is the same that all Amiga owners deal with, the lack of memory protection. I remember reading somewhere, maybe here, that Amiga OS 4.1 does in fact have memory protection, but it's turned off to keep compatibility with older software. Personally, I'd rather have a reliable system than old software, so is it possible to turn the memory protection on?

Are there any guides from Hyperion to do this?

I know some will say it's a problem with my system, but it's been like this since clean install, and I can write C programs which will crash the Sam 100% of the time, so I really doubt it's a hardware problem or bad RAM or something.

Any help appreciated.

Cheers

Garry

@thegman

>I can write C programs which will crash the Sam 100% of the time

Me too, but then I'm rubbish at programming!


>but it's been like this since clean install

So OS4 crashes by itself? What programs are you running when it crashes? Can yo describe the behaviour in more detail?

Most people find OS4 very stable, but occasionally, old programs can mess things up. Search for "petunia blacklist" and "jit blacklist" on the main amiga sites to see what software causes problems or wade through this thread for some useful info.

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@thegman

Quote:

I can write C programs which will crash the Sam 100% of the time

Sure, i can crash my windows machine only deleting one file

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@Fransexy

OT: Sorry
Quote:

Sure, i can crash my windows machine only deleting one file

Registry ?

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@thegman
I all with you here. I would love having memory protection in AOS even though it would mean that it would break compability with a lot of older apps, or even that I would have to have two installations of AOS (one with and one without mp). But lets see what the future, and the brilliant minds at hyperion, brings

Quote:

Sure, i can crash my windows machine only deleting one file

What does it have to do with the original problem ? This won't improve the reliability of OS4...

People don't care about that, all they want is running their 20 years old software. So it's better to have a system that can be crashed with a badly written program than a reliable one with new software...

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@All

The Sam won't crash just by itself, but I had a crash just going to a website with IBrowse, and pasting text in CodeBench will crash the machine too. I don't mind if a program crashes, that's just a mistake in the program, we all do it from time to time. I've got a problem with the whole system crashing along with my unsaved work and leaving me unable to look at crash logs or anything, as its completely hung.

The worst problem is probably running shell programs, the program crashes leaving the shell useless, and it can only be closed using Scout. If I do that, Scout itself crashes and often I'll get a full system hang after that.

If anyone has any suggestion on how to improve things I'd love to hear them, particularly the shell program issue.

Cheers

Garry

@thegman
Quote:

If anyone has any suggestion on how to improve things I'd love to hear them, particularly the shell program issue.

First, stop using Scout or any other "kill" program to force windows (or any other resource) to disappear. That has never been legal in AmigaOS and it puts the entire system into an indeterminate state. Problem solved.

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@thegman

Contact the developer directly if you can reproduce problems, don't just say "it crashes". We're all here from time to time and keen to help.

For Codebench, contact Rigo.

For shell/console, contact me (by PM, not in public). Although you're dealing with an old version, I might be able to help.

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tony

Hyperion Support Forum: http://forum.hyperion-entertainment.biz/index.php

@thegman

Quote:

leaving me unable to look at crash logs or anything, as its completely hung.

C:DumpDebugBuffer


Quote:

The worst problem is probably running shell programs, the program crashes leaving the shell useless, and it can only be closed using Scout. If I do that, Scout itself crashes and often I'll get a full system hang after that.

Increase you default shell stack, to reduce this sort of crash. Many programs don't yet have stack cookies.

Don't kill the window, iconify it or minimize it and push out the way till your ready to reboot.

Don't do any vital work with a crashed program in your system, even with this magical memory protection, you'd be asking for trouble.

What programs are crashing anyway?

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Unfortunately this is something you can't do anything about. And this will happen in all three (AROS. MOS, OS4). You cannot incremently add memory protection to the current system. The only way to do that is to rewrite something that would take care of that. This would mean rewritting applications as well (current OS4 apps won't be protected).

That's what I keep on saying... Main argument is that no one can afford this big change...

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@thegman

AmigaOS 4 does have memory protection, it uses the MMU to protect internal system structures, etc. But the AmigaOS API by design lets applications access many of its structures and if it would no longer allow that, you would lose all backward compatibility, because most programs rely on it, and many programs create several tasks which all access the same memory structures, so they rely on being able to access common memory, so if the OS would prevent tasks from accessing memory allocated by other tasks, again you would lose all backward compatibility. You can specify MEMF_SHARED when allocating memory if you want that memory to be accessible by other tasks and doing this is encouraged, but most old applications just allocated memory as MEMF_ANY and if OS4 would only allow MEMF_SHARED memory to be accessed by other tasks, then again none of the older applications would work anymore...

However I think that many of the problems you experience are not caused by the lack of memory protection. You should keep in mind that the current OS4 for Sam is a BETA release, and it's very likely that once the FINAL non-beta version of OS4 is released for the Sam you'll find that things are much improved and a lot more stable.

@yoodoo2
Owb 3.9 and Wookiechat has a tendence to crash on me which sometimes requires a reboot.
This is on a Sam running OS4.1.

Just because it is a modern app does not mean it is completely bug free. I have seen modern apps crash on windows and linux as well like for example Firefox. The difference is that it dosent take the OS with it.

Last edited by Tomas on 09-Apr-2009 at 09:28 AM.

@COBRA
Is it not possible to have both?? Memory protection for new and native apps while older software without.

@COBRA
Again it is a question of the chicken and the egg. If programmers cant test their program in a memory protected environment, they do not specifically design their app to work with MP. On the other hand, the OS developers will be hesitant to add MP since a lot of programs will cease to work.
Maybe a short term solution could be to add a switch in preferences where an user could flick memory protection on/off. Only a few programs would be able to run in this environment, but after a couple of years, hopefully, the majority of active projects would be designed to work with MP

@Tomas

It would be possible with an entirely new API, while running the old applications in a separated emulated/virtual environment (like UAE/sandbox), but you couldn't have old apps interact with the new ones, and all applications would have to be rewritten because of the changed API, so porting them to the new OS would be a very difficult and time-consuming task.

@Tomas

Exactly, I'm not asking applications not to crash, I just want the OS to remain stable if one does.

And I know continuing to work on an unstable system is a bad idea, but if I rebooted everytime I thought it was a bit shaky, I'd be doing it a lot.

OS 4.1 for Sam may well be beta, but I fear that even after the full release, the unreliability will remain, as it's pretty much designed in, to allow userland apps to meddle with internal structures, and while the OS allows this, it will always be unstable.

I will contact some developers off-forum, though, thanks for the offers.

Cheers

Garry

@ssolie

Exorcist is a nice Program to kill or disappear hang tasks, it often leaves the system stable.
On the other hand a warm reboot on sam takes only 10 seconds. But not everybody wants to reboot and open all the programs and tools again to reach the workflow like befor the reboot.

It´s a a two-edged sword

I must admin that Amiga OS4.1 is very stable for a beta!
I use it every day and freezes or crashes appear only in very rare amounts and only if i experiment with legacy software.

Last edited by fingus on 09-Apr-2009 at 09:47 AM.
Last edited by fingus on 09-Apr-2009 at 09:47 AM.

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@thegman

The main problem is basic concepts like message-passing under AmigaOS, applications just allocate blocks of memory, put pointers to them into message structures, and send the messages, then the message ends up being processed by another task which may send it to yet another one, etc. and so memory must be shared if it's to be accessed by all tasks. What some other OS'es do is they don't allow this "passing pointers around" approach, and they physically copy all the data when it's transferred from one task to another. While this may be safer, it is much, much slower, and this is one of the reasons AmigaOS is so fast and responsive compared to other OS'es, not even mentioning the overhead created by having to reload the MMU table each time a context switch takes place. If AmigaOS did it that way it would cause significant slowdowns, so even if you're prepared to throw away backward compatibility and happy with running existing and older apps via an isolated emulation environment like UAE, you also have to accept the performance losses.

If you want additional memory protection, then I think you could have memguard running in the background, it catches a lot of misbehaving programs before they do any damage, and quite a few people actually run memguard all the time.

@COBRA

Hi,
This memguard sounds interesting, I'll check it out.

I'm familiar with message passing techniques, as I used to work with QNX Neutrino quite a lot. QNX offers the same sort of thing, passing around shared memory. The messages themselves are copied for safety, but any large amount of data is in a shared space, still protected from damaging the kernel, but user apps can share it. This worked very well, and QNX is exceptionally fast.

If there were any performance losses, I'd be very willing to accept them to get a stable system, but I think QNX shows that one does not necessarily have to have one or the other.

Anyway, I'll look at memguard, it may be just what I'm after.

Thanks

Garry