Messages in this thread | | | Date | Sat, 18 Aug 2007 11:21:02 -0800 | From | "Brennan Ashton" <> | Subject | Re: power off disk drives while running |
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On 8/18/07, Jan Engelhardt <jengelh@computergmbh.de> wrote: > > On Aug 18 2007 12:08, Marty Leisner wrote: > > > >In embedded system design, it may be useful to poweroff the disks (as opposed > >to merely spinning them down). We want to leave the system running while > >the disk is powered down, and let the disk powerup when it needs to be > >spun up. > > That means you also have to power it on... > > >While the "power off mechanism" would be platform dependent, is there a > >generic path to announce "prepare for power going away"? > > I do not see why that would be needed from a software point of view. Just make > sure that the disk does not needlessy emergency-park when pulling power. When > someone wants to write to disk, the request goes to the device driver, which > hands it to the controller, which hands it to the disk. And your controller > should be able to handle it (e.g. wait until reconnect) when there is a request > for a disk that is powered off. > > > Jan > -- > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
I see this a a very important feature in the embedded system relm, I have worked on two projects that required extreme power management, and massive data storage. The ability to fully turn off a drive while the system is running is key. It seems like this should be able to be done from a kernel point of view rather than extra hardware. Although if is not in the IDE/SATA spec then extra hardware would be necessary. -- Brennan Ashton Bellingham, Washington
"The box said, 'Requires Windows 98 or better'. So I installed Linux" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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