From: firstname.lastname@example.org (N. Thornton)
Subject: Re: Q. why 5400 and 7200 rpm disk drives?
Date: 10 Oct 2002 12:43:32 -0700
NNTP-Posting-Date: 10 Oct 2002 19:43:32 GMT
"PCS Electronics" wrote in message news:...
> What about 10.000 rpm and 15.000 rpm drives than? :-)
10,000 rpm is really 9999 rpm, so Woodgate's Numerology Law still
15,000rpm is a paradoxical application of this law which NO-ONE is
allowed to disclose. OK, you may never hear from me again...but you
people have got to know. 15,000 rpm drives break the law!! And that's
why you get radiation peaks in your home. But don't tell anyone!!
> "John Woodgate" wrote in message news:6wWbaaAr6Sp9Ewg8@jmwa.demon.co.uk...
> > I read in sci.electronics.design that Winfield Hill
> > wrote (in ) about 'Q. why 5400 and 7200
> > rpm disk drives?', on Wed, 9 Oct 2002:
> > > Hmm, why did disk drive manufacturers settle on rotation speeds
> > > like 5400 and 7200 rpm? These correspond to 90 and 120 rps, or
> > > 1.5 and 2.0 rotations per ac cycle for 60Hz ac power. Early disk
> > > drives ran at 3600rpm = 60Hz, and perhaps some ran from ac motors,
> > > and such numbers would make sense for a synchronous ac motor.
> > >
> > > But modern disk drives run from dc power, and therefore should
> > > not be beholden to any ac-power parameters. While it's true that
> > > the bleeding-edge of new disk-drive performance is in 10000 and
> > > 15000 rpm drives, etc., we still see impressive new 5400 and 7200
> > > rpm drives. So, hey, what's the deal? How come no spec. creep?
> > > E.g., no 6000 rpm versions to out-compete the 5400 rpm models?
> > > Is there in fact some engineering magic in 5400 and 7200 rpm?
> > >
> > For reasons that I am not allowed to disclose, the digits have to add up
> > to 9. 3+6+0+0 = 9, and so on.
> > --
> > Regards, John Woodgate, OOO - Own Opinions Only.