Talk:Non Maskable Interrupt

Quote Breakup?

What should we do with Brendan's quote? Also, how does one update a forum link like that? I couldn't find how, although I think I've seen it somewhere before. --Alboin

Post:83433 for the links. As for the quote, I don't know enough about the NMI to rewrite things - Combuster 10:33, 10 July 2007 (CDT)

Comments

Is it really wise to turn off NMI? okay, if you get an NMI while you're switching from RealMode to ProtectedMode, you could get a Triple Fault, which would reset the system, but isn't a system reset wished when content from memory is unreliable by that time ? -- Pype.

Is there much you can do if an NMI occurs? I guess if you got the error while reading from something that was copied from a disk at some point in the past and not modified since then you could read it from the disk again and continue with the (hopefully) good copy, but if it's something that has changed or been created dynamically then you don't really have an easy way to recover other than essentially starting from scratch. -- TheKemp

Of course, you're assuming that the kernel code hasn't been corrupted, if the kernel is damaged then you'll most likely triple fault anyway. The best course of action is probably to request the user perform a RAM diagnostic with ~MemTest or something (and hope you don't crash before you can get that far). Then again... Windows keeps a "Hardware Damaged" flag for every physical page of RAM, unfortunately this would mean aborting the program that was running when the NMI occured then checking each page the program was using at the time for what are basically "bad sectors" and flaging them so they aren't used again -- AR

So if an NMI occurs you should assume it'll continue happening at that location in future rather than it being a freak occurrence? -- TheKemp

I'm not an engineer so I wouldn't know for certain, but I would be inclined to think that if an NMI occurs on a page when you retest the program that caused the original NMI then it would seem rather likely that the chip is faulty, I don't know if Windows persists the flags across reboots but I doubt it since AFAIK it's impossible to tell if the RAM has been replaced while the computer was off. If the NMI doesn't occur again while checking the pages then the fault isn't severe and could be written off, just if it is a persistent problem then the page should probably be disabled (in the interest of preventing random program crashes) -- AR

Added Brendan's information from the forums, could probably do with being organised better but at least it's here for now. -- TheKemp