Date: Mon, 8 Jan 2001 19:58:56 -0600 From: "Jason Smethers" <jsmethers@pdq.net> To: "Chris Dillon" <cdillon@wolves.k12.mo.us> Cc: <chat@FreeBSD.ORG> Subject: Re: ECC worth the extra cost for SOHO server? Message-ID: <008d01c079df$baaad680$edcf1f40@pdq.net> References: <Pine.BSF.4.21.0101081828020.4671-100000@mail.wolves.k12.mo.us>
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From: "Chris Dillon" <cdillon@wolves.k12.mo.us> > Out of curiosity, how does the OS know exactly what event triggered > the NMI? I know what an NMI can mean, but I don't know what it REALLY > IS, you know what I mean? The technical answer for exactly what an > NMI is and what it consists of is welcome. :-) I'll take a shot, though it has been a while since I did anything with interrupts, and this bypasses the explanation of interrupts delivered by memory instead of hardware... Basically you have two types of interrupts. There are Maskable Interrupts such as those delivered by software or hardware that need servicing but can be ignored, usually once the request has been accepted. These interrupts can be masked off in the [A]PIC ([Advanced] Programmable Interrupt Controller) so that further interrupts are not received until the mask is reset. Then there are Non-Maskable Interrupts (NMI). These interrupts can not be ignored and are serviced immediately. The processor usually receives the interrupt as any other except that a pin on the processor is asserted to make it a NMI. - Jason To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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