spin down an IDE hard drive, to conserve power



This code is public domain (no copyright).

You can do whatever you want with it.



　　Time to

Drive　　return to　　　　Power

state　　ACTIVE state　　　　consumption

-----　　------------　　　　-----------

ACTIVE　　zero　　　　　　highest

IDLE　　less than STANDBY(?)　　less than ACTIVE

STANDBY　　up to 30 seconds　　less than IDLE

SLEEP　　(must reset drive)　　lowest



Both idle and standby can use a timer built into the drive

(IDLE/STANDBY commands instead of IDLE IMMEDIATE/STANDBY IMMEDIATE).



SLEEP state can only be exited by resetting the drive