Messages in this thread | | | Date | Mon, 31 Jul 2000 16:15:55 +0200 | From | Matthias Andree <> | Subject | Re: (reiserfs) Re: sync: why disk cannot spin down |
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On Mon, 31 Jul 2000, Xuan Baldauf wrote:
> Xuan Baldauf wrote: > sync; hdparm -C -Y /dev/hda; sync; hdparm -C /dev/hda
Note that "sleep" mode is quite different from "standby" mode. Drives spin up from standby mode by themselves, they are NOT supposed to wake up from sleep mode, unless you issue a reset.
Sleep mode is meant to put the drive to sleep, possibly switching the laptop off or something.
We happen to be so lucky that the Linux kernel issues a reset if it is fed up with IDE timeouts, which will bring the drive back online, at the expense of voiding all settings in that IDE channel, particularly, DMA modes, PIO modes and the like, unless you use the "keep options over reset flag". (which means soft reset, effectively).
Admittedly, drives should use less power in sleep mode, the price is higher latency and, as said before, possibly loss of drive configuration.
-- Matthias Andree
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