Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!ncoast!davewt From: davewt@NCoast.ORG (David Wright) Newsgroups: comp.sys.amiga.advocacy Subject: Re: Why are Amigaoids hell bent on proving the Amiga is better ? Message-ID: <1991Jun29.150321.9791@NCoast.ORG> Date: 29 Jun 91 15:03:21 GMT References: <1991Jun27.170049.21231@grebyn.com> <1991Jun29.005127.17803@grebyn.com> Organization: North Coast Public Access Un*x (ncoast) Lines: 29 In article <1991Jun29.005127.17803@grebyn.com> ckp@grebyn.com (Checkpoint Technologies) writes: >In article greg@pfloyd.lonestar.org (Greg Harp) writes: >>I have always had a bit of a beef with this one. What the *hell* kind of >>good does 1 parity bit do you? >It does exactly one bit more good than no bits. :-) No, actually it is WORSE, at least in the brain-dead way that IBM clones use it. If you have 1 bit out of 9 for parity, with no error correction, that means that more than 10% of the time the error will be in the parity bit itself. Since PC clones are not designed to have any ECC bits, and the whole parity detection system is incredibly archaic, a parity error just brings the whole machine to a halt, even when it is in the parity bit itself. I cetainly call this "less reliable", since you have now added a "feature" that will cause the computer to seemingly "fail" over 10% more than it normally would. Further, the PC is too brain-dead to even see where the address is, and whether it is in use. A parity error outside of active memory should, at the most, pop up a requestor notifying you it occured, without halting the system at all (oops, PC don't have multitasking). I have been working with PC's since the first IBM "PC" (not even XT) came out, and in ALL THAT TIME, I have only seen 2, thats *TWO* parity errors. Both of which were over 6 years ago. And they occured on fairly low-quality RAM boards at that. So what this means is that all PC clone owners, whether they would want it or not, have been force to buy over 10% more RAM than they need, for a "feature" that was at best only crudely implemented, and which increases the posibility of false "errors" and MTBF by over 10%. Great deal there. Dave