Path: utzoo!attcan!uunet!decwrl!sdd.hp.com!ucsd!tut.cis.ohio-state.edu!pt.cs.cmu.edu!MATHOM.GANDALF.CS.CMU.EDU!lindsay From: lindsay@MATHOM.GANDALF.CS.CMU.EDU (Donald Lindsay) Newsgroups: comp.arch Subject: Re: Data Storage density questions Message-ID: <10065@pt.cs.cmu.edu> Date: 1 Aug 90 15:31:14 GMT References: <2684@network.ucsd.edu> <1990Jul31.200043.5189@nlm.nih.gov> <1990Jul31.233407.11825@portia.Stanford.EDU> Organization: Carnegie-Mellon University, CS/RI Lines: 18 >In article <1990Jul31.200043.5189@nlm.nih.gov> states@tech.NLM.NIH.GOV (David States) writes: >Aerodynamic heating becomes a problem at higher velocities, >but you don't hit the speed of sound until ~120,000 RPM. With aluminum platters, the upper limit for RPM is set by the fact that high centrifugal forces are bad for the platter lifetime. I suppose we could switch materials, but as David Hinds just pointed out, higher RPM makes it harder to get higher bits/inch. Of course, we could always cool the platters (-: [It's been done! Cub scout's honor! Check out the IBM JR&D in, ahhh, the very early seventies. They built a R/W optical disk that [only] worked at cryogenic temperatures. The article had scope traces, and like that.] -- Don D.C.Lindsay