MMU and memory test

[demolition]

After moving my ACA1232 to the NOS 1200 I got, I wanted to make sure it was completely stable and didn't need any extra timing fixes. Thus, I tried to run MBRTest to let it keep running a memory test in a loop. When running it under WB, it very quickly froze the machine. After a reboot, it froze in exactly the same spot. Then I did a warm reboot and started it up without startup-sequence. Still froze at the same address. After doing a cold reboot though, it seemed to run fine, and I had it running for 2½ hours without problems after which I turned it off.

I have mmu.library installed, so I'm thinking maybe the MMU would be the cause of the freezing when the program tried to test a locked part of the memory? Since MBRTest starts by turning off the OS, it couldn't catch the exception and just froze.

Does it sound like the explanation? Also, does a warm reboot not reset the MMU?

[prowler]

Originally Posted by demolition

I have mmu.library installed, so I'm thinking maybe the MMU would be the cause of the freezing when the program tried to test a locked part of the memory? Since MBRTest starts by turning off the OS, it couldn't catch the exception and just froze.

Does it sound like the explanation?

Sounds good to me. Never attempt to use a memory test utility with memory management running whatever the platform. Such utilities incorporate their own driver to make the memory available. Always start from a cold reboot and nothing else loaded.

Originally Posted by demolition

Also, does a warm reboot not reset the MMU?

Evidently not.

[hooverphonique]

Originally Posted by demolition

Also, does a warm reboot not reset the MMU?

It shouldn't.. it would ruin the option of softkicking using the mmu..

[demolition]

Originally Posted by hooverphonique

It shouldn't.. it would ruin the option of softkicking using the mmu..

Obviously that makes sense.

[daxb]

I think running a memory test programm successfull doesn`t mean you have a stable system and the same for the opposite. "Using" the system a lot it IMHO better.

About mmu.library: I know MuTools can`t be use before SetPatch (e.g. start without s-s). So mmu.library is first available after SetPatch. MMULibs docs have a lot to read.

[demolition]

Originally Posted by daxb

I think running a memory test programm successfull doesn`t mean you have a stable system and the same for the opposite. "Using" the system a lot it IMHO better.

True, but it is a very good indication though, and nothing will ever be 100%. I am 95% certain that it is running as it should now, however time will tell me about the last 5%.

If it crashes during normal usage it also doesn't mean that it is unstable, and it can be a lot harder to reproduce. Amiga software is not always of the best quality.

Whenever I had instability issues with an Amiga, I have so far always been able to trigger it with MBRTest, so it seems like a good test to me.

[GadgetUK]

Forgive my ignorance... I understand that mmu.library provides mechanisms for software to make use of the mmu etc, but what uses it - why do you have it installed?

[demolition]

The main usage is either softkicking a kickstart ROM (which I don't need since the ACA can do it as well) or use it for debugging purposes since you will know if a program tried to access a part of memory it is not supposed to. The last part is what I wanted to use it for.

[GadgetUK]

Ah ok, I can see how that would be useful in debugging code. Also just read that some z80 emulation makes use of it.