Date: Wed, 09 Aug 2000 14:31:09 -0600 From: Warner Losh <imp@village.org> To: chip@chocobo.cx, Alan Clegg <abc@firehouse.net>, freebsd-stable@FreeBSD.ORG Subject: Re: Flash disk support over USB? Message-ID: <200008092031.OAA50408@harmony.village.org> In-Reply-To: Your message of "Tue, 08 Aug 2000 17:08:31 MDT." <200008082308.RAA44002@harmony.village.org> References: <200008082308.RAA44002@harmony.village.org> <20000808152310.A34869@setzer.chocobo.cx> <14736.11357.195584.7158@trooper.velocet.net> <20000808120450.G38455@diskfarm.firehouse.net>
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In message <200008082308.RAA44002@harmony.village.org> Warner Losh writes: : In message <20000808152310.A34869@setzer.chocobo.cx> Chip Marshall writes: : : Out of curiosity, why don't IBM microdrives work in these units? Does : : that apply just to this specific type of CF reader, or to all USB CF : : readers? : : That's unknown at this time. We know that IBM Microdrive works with : the pccard code. I'd also like to add that the microdrives have a much higher current requirement than the CF spec guarantees, especially for spinup. Maybe the CF reader device was unable to deliver the power in such a way as to damage the microdrive. The microdrives do no exceed what the pccard spec says is acceptible limits for the card's power. Therefore, there might be an electrical basis for this particular card reader not working. Maybe they have a bad failure mode for an overcurrent condition. Without measurement tools and motivation to look at this more closely, who can say. The newer 1G microdrives use much less power on powerup, and should work with a wider range of devices. I think they exceed the specs briefly on powerup, but their normal operation is well below the specs. The current family uses more power all around. One thing that the drives might force in FreeBSD is that they use far less power when they are in suspend and standby mode than when in full operational mode. It would be desirable to to agressively move into standby and quickly move to suspend mode. The normal operating current is 350mA, while the standby mode is 175mA and the suspend is like 90mA, IIRC. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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