Thanks Bjorn & Dmitri. Do you think i can power the USB enclosure externally with say a 6V (500mA) supply, and that do the trick (i think most power adapters that you find with telephone/answeringmachine etc. fit that range, atleast in the US)...!!!
powering thru the IDE directly might be heck of a job for me, coz' i'd have to saw apart the IDE connector or rip off the soldered leg. bdutta. --- >From: Dmitri <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >CC: Bj�rn Stenberg <[EMAIL PROTECTED]>, banibrata dutta <[EMAIL PROTECTED]> >Subject: Re: [Linux-usb-users] USB HDD enclosure not detected by kernel >(RH7.2) >Date: Tue, 8 Jan 2002 08:13:47 -0800 > >Quoting Bj�rn Stenberg <[EMAIL PROTECTED]>: > > > Dmitri wrote: > > > > > I would *very much* doubt that the HDD can be fed with USB power. Most > > > HDDs are really power-hungry, and they want dual (+5V, +12V) power > > > supplies. > > > > Actually 2.5" harddisks don't use +12V, only +5V. It seems most drives > > need more than the maximum 2.5W when spinning up but less when in use. >So, > > theoretically, you could solve the power-up surge with a really big > > capacitor or something, but you'd still be pushing the limit. > >Indeed I remember playing with 2.5" HDD couple of years ago, it had a >small adapter and just IDE connector on the other side... but the FAQ from >the Chinese site mentioned +12V, and I focused on that. Maybe it is not >relevant to the drive being used. > > > Since disk power loss is a rather unpleasant experience, I personally > > would not trust a unit that tries to live off the USB power. > >This gives me the idea why the older laptop CRASHED upon plugging the >device in. I think, it overloaded the bus, and the root hub generated the >appropriate event (overload). But it is a rare event, and probably was not >debugged well in earlier revisions of the OS. That's why it could crash. > >Even worse, if that older laptop wasn't equipped with the required USB >power switch (something like Micrel MIC2025) then the power on the whole >section of the motherboard could be compromised, which could *easily* halt >the CPU. > >The newer driver / new laptop didn't crash, but since the overload on port >is pretty much hopeless anyway, that could explain why no device connect >was produced - because there was no power! This can be tested with just a >voltmeter. > >Another reason to suspect bad power is that some [small] notebooks have >root hub ports that are only capable of 100 mA, not 500 mA as they should >be. If so, the solution is simple - use the self-powered hub, or just cut >the +5V line and connect it (drive side, of course!) to the external, good >+5V power supply. > >Thanks, >Dmitri > >-- >Codito, ergo sum - "I code, therefore I am" ><< attach3 >> _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
