Date: Mon, 25 Nov 1996 22:54:09 -0500 From: Joel Ray Holveck <joelh@gnu.ai.mit.edu> To: terry@lambert.org Cc: msmith@atrad.adelaide.edu.au, terry@lambert.org, grog@lemis.de, chat@FreeBSD.org, smut@clem-162.dorms.tamu.edu Subject: Re: SCSI A/V drives Message-ID: <199611260354.WAA10790@hill.gnu.ai.mit.edu> In-Reply-To: <199611252319.QAA23592@phaeton.artisoft.com> (message from Terry Lambert on Mon, 25 Nov 1996 16:19:29 -0700 (MST))
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> Okay, understood... I hadn't realized that the recal was a > time-consuming process. Why does the drive logic not continuously > update the thermal expansion factor it uses, each time it seeks? Because the thermal expansion fact varies radially based on the current expansion minus the expansion ath the time the drive was formatted. So it isn't constant across the whole disk surface as it would be if the track lines were parallel instead of concentric circles. So the calibration factor is actually a function which can't be predicted by a single point. Fair enough, although it would seem that the calculations could be made from the data acquired during the normal seeks, whether it's a single factor, multiple coefficients, or a lookup table. Of course, I'm talking about things I don't know, but then again, I'm talking about things I want to understand. Thanks, Joelhome | help
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