Hannes Reinecke <hare@xxxxxxx> writes: >> forever. This is according to SAT specs. There is no command to explicitly get >> out of standby-mode. Even a reset should not change the drive power state >> (though I do see a lot of drive waking up on COMRESET). A media access command >> does that. See ACS specs "Power Management states and transitions". The only >> exception is that you can use SET FEATURE command to wake up a drive, but only >> from PUIS state (Power-Up in Standby), which is a different feature that is not >> necessarilly supported by a device. IIRC, there was a bit in the IDENTIFY block that if set, meant that the drive WOULD NOT automatically spin up on access, and you HAD to use SET FEATURE to wake it. I seem to recall that my Western Digital drives did this and my bios would not recognize the drives as bootable because it did not know how to issue SET FEATURE to force it to spin up.