Date: Thu, 23 Mar 1995 20:58:09 -0800 (PST) From: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> To: babkin@hq.icb.chel.su (Serge A. Babkin) Cc: freebsd-hackers@FreeBSD.org Subject: MTBF and what it means (Was: Re: Why IDE is bad) Message-ID: <199503240458.UAA02981@gndrsh.aac.dev.com> In-Reply-To: <199503241335.IAA00423@hq.icb.chel.su> from "Serge A. Babkin" at Mar 24, 95 08:35:53 am
next in thread | previous in thread | raw e-mail | index | archive | help
[Retitled MTBF and what it means] > > > On Thu, 23 Mar 1995, Joe Greco wrote: > > > > > > > 4) writing the disk more may wear it out faster. > > > > > > > > Now there's one for the books! :-) > > > > > > With an 800,000 hour MTBF, I think that enough years will > > > have passed that even if I reduce the lifetime of the > > > disk by 75%, I'll be too old and grey to care when it > > > dies. (yes I am sure the original comment was to see if > > > we were all awake :-) but it's a good point). > > > > I did once see someone wipe a disk clean, by doing continuous > > read/write/read cycles on it. The first disk went in 3 months, then > > three months later the second disk (and the programmer, by the way) > > went. So I think it can happen, but probably not with the kinda load we > > see. > > Some information for everybody who thinks that MTBF is equal to the lifetime: [Good sample of how MTBF is arrived out deleted] > Therefore MTBF 800,000 hours doesn't means that HDU will work 800,000 hours > before a failure, it only means that if lifetime is near 10,000 hours then > near 1/80 of all sold HDUs will die before reaching the lifetime. And now you know why 800,000 Hour (22 years) MTBF disk drives come with a 5 year (43,800 hours) warranty. > I'm sorry if I had translated some terms to english wrong. Looked pretty good to me. So many people miss understand what all this MTBF is. -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Custom computers for FreeBSD
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199503240458.UAA02981>