From owner-freebsd-chat Tue Jan 9 8:32:36 2001 Delivered-To: freebsd-chat@freebsd.org Received: from mail.wolves.k12.mo.us (mail.wolves.k12.mo.us [207.160.214.1]) by hub.freebsd.org (Postfix) with ESMTP id 537EA37B6B4 for ; Tue, 9 Jan 2001 08:32:18 -0800 (PST) Received: from mail.wolves.k12.mo.us (cdillon@mail.wolves.k12.mo.us [207.160.214.1]) by mail.wolves.k12.mo.us (8.9.3/8.9.3) with ESMTP id KAA15678; Tue, 9 Jan 2001 10:31:51 -0600 (CST) (envelope-from cdillon@wolves.k12.mo.us) Date: Tue, 9 Jan 2001 10:31:50 -0600 (CST) From: Chris Dillon To: Jason Smethers Cc: chat@FreeBSD.ORG Subject: Re: ECC worth the extra cost for SOHO server? In-Reply-To: <008d01c079df$baaad680$edcf1f40@pdq.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Mon, 8 Jan 2001, Jason Smethers wrote: > From: "Chris Dillon" > > 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. That clears a lot up. I'm beginning to remember a discussion about NMIs a couple of years ago that happened on one of these lists. :-) -- Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net FreeBSD: The fastest and most stable server OS on the planet. For IA32 and Alpha architectures. IA64, PPC, and ARM under development. http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message