Return to BSD News archive
#! rnews 4277 bsd Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!spool.mu.edu!agate!reason.cdrom.com!usenet From: "Jordan K. Hubbard" <jkh@FreeBSD.org> Newsgroups: comp.os.linux.hardware,comp.os.ms-windows.win95.misc,comp.os.os2.setup.misc,comp.unix.bsd.freebsd.misc Subject: Re: HELP: Can I mix memory speeds Date: Mon, 22 Jul 1996 12:05:29 -0700 Organization: Walnut Creek CDROM Lines: 64 Message-ID: <31F3D0F9.41C67EA6@FreeBSD.org> References: <4s7rae$m3a@symiserver2.symantec.com> <stephenkDutwB2.52D@netcom.com> <31F2C467.167EB0E7@FreeBSD.org> <stephenkDuxJLE.EDr@netcom.com> NNTP-Posting-Host: time.cdrom.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0b5a (X11; I; FreeBSD 2.2-CURRENT i386) To: Stephen Knilans <stephenk@netcom.com> Xref: euryale.cc.adfa.oz.au comp.os.linux.hardware:45238 comp.os.ms-windows.win95.misc:162294 comp.os.os2.setup.misc:17529 comp.unix.bsd.freebsd.misc:24226 Stephen Knilans wrote: > First, I am NOT showing ignorance here. Are YOU saying that DOS or VMS or > whatever are IMPERVIOUS to memory errors? No, I'm not saying that. You're not actually reading what I'm saying, that much is clear. What I said before and will say again is that parity is an *aid* to diagnosing memory problems and it's only you here who seem to feel that it's falling short as a universal solution to all reliability problems. That's your own misunderstanding of Parity memory, not mine. I'm well aware of its limitations, and ECC is certainly a nicer way to go IF your motherboard supports it and IF you're willing to take a performance hit (do some benchmarks with the latest ASUS motherboards and different memory types) in exchange for the added reliability. If all you want is the first level of "safety belt" then parity is cheap insurance. > and ECC. Parity DETECTS errors and aborts. It is *****NOT***** fault tolerant > as I generally hear the term. ECC CORRECTS many errors and generally I don't know how you generally hear the term, but all of this is entirely off the point. You said that advocating the use of parity memory was stupid, I said it clearly wasn't when compared to the no-parity alternative. We can go on all day about *additional* mechanisms for creating fault tolerant systems, but that wouldn't have anything to do with the original points I was rebutting. > Need I mention that the chance of a power failure in someway is almost 100% per Again, this is off-topic. Of course I use a UPS. I've got 2 sitting at my feet right now providing protection for my home equipment, and the sites I deal with generally have something considerably more beefy in a power closet. > A parity system, by contrast would generally CRASH. I guess, if you intercepted > the parity error in the O/S, you COULD block out memory, etc... That, You're just not listening here. It would not CRASH, it would panic. There's a major difference since a parity-error induced panic tells me right away that it's time to start swapping memory and/or cache, and I will certainly do so in response. I'm not going to try to do something so ludicrous as "block" memory addresses, I'm going to REPLACE the whole frigging bank when I see one of these problems. If they persist, I'll swap the cache, the motherboard, whatever it takes. If I'm just seeing random weirdness, I've got a much longer list of suspects. > So, how many people here have parity memory for safetys sake, but plug their > systems in the wall, and handle computer boards like a deck of cards? What's your point? We might as well ask "how many of you have parity memory but sleep with cheap hookers without wearing a condom?" for all the relevance to this discussion that aside has. I'm not trying to play watchdog for the entire human race, simply to point out that it's entirely wrong to say that Joerg is making "STUPID" assertions when he states that parity has some value. > BTW Go ahead Jordan and ignore my advice. The UPS idea ALONE kept the > computer at my job running through DOZENS of power failures. HERE, it Bully for you. You want an award for remembering to zip up before leaving the men's room, too? :-) -- - Jordan Hubbard President, FreeBSD Project