Path: utzoo!attcan!uunet!ginosko!gem.mps.ohio-state.edu!rpi!batcomputer!mha From: mha@batcomputer.tn.cornell.edu (Mark H. Anbinder) Newsgroups: comp.sys.mac Subject: Re: Serial numbers of SE/30 40 and 80 Drives that Apple will replace? Message-ID: <8652@batcomputer.tn.cornell.edu> Date: 20 Aug 89 15:34:18 GMT References: <2363@taux01.UUCP> Reply-To: mha@tcgould.tn.cornell.edu (Mark H. Anbinder) Organization: Baka Industries, Ithaca, New York Lines: 34 In article <2363@taux01.UUCP> cyosta%taux01@nsc.nsc.COM ( Yossie Silverman ) writes: >What are those serial number ranges? I have a bad 80 in my SE/30. I wonder >if it is in that range. The amazing thing is that I can make the drive >startup always by turning on the mac while it is laying on its face. Lately >the drive will NOT spin up unless I place the mac on its face first at all! >All you people that have this problem and would like to spin up at least once >in order to backup the drive, try turning on the mac while it is in a position >other than upright. Physics tells us that spinning objects tend to keep spinning in the same plane. Because of this, tilting a spinning object, especially a rapidly spinning one, is difficult. My high school physics teacher, all those years ago, illustrated this by having a student hold a bicycle wheel, which he set to spinning. The student, instructed to tilt the wheel so it was horizontal, was always astounded at how much effort it took. As a corollary, successfully tilting a rapidly spinning object can create an imbalance, even if temporary, in its spin. One of the best reasons NOT to move a computer with an internal hard drive, or an external hard drive by itself, is that changing the plane of spin can cause enough imbalance that the spinning platter can physically collide with the head, causing extensive damage to the disk, and the possibility of total loss of data. Are you sure that's what you want to risk by turning your Mac on its front and starting it up, then tilting it to the upright position? You may well have a better chance of recovering your data by bringing the drive to your dealer and asking them to recover whatever's still there before replacing the drive. -- Mark H. Anbinder ************************** mha@tcgould.tn.cornell.edu BAKA Industries ** (cornell!)biar!memory!mha 200 Pleasant Grove Rd. H: (607) 257-7587 ******** Ithaca, NY 14850 W: (607) 257-2070 ******* "It's not safe out here." Q