jacks@Gen4:~$ sudo hdparm -s 1 -S 4 /dev/sdb /dev/sdb: Use of -s1 is VERY DANGEROUS. This requires BIOS and kernel support to recognize/boot the drive. Please supply the --yes-i-know-what-i-am-doing flag if you really want this. Program aborted.
-s is poweron_standby in the conf
-s Enable/disable the power-on in standby feature, if supported by the drive. VERY DANGEROUS. Do not use unless you are absolutely certain that both the system BIOS (or firmware) and the operating system kernel (Linux >= 2.6.22) support probing for drives that use this feature. When enabled, the drive is powered-up in the standby mode to allow the controller to sequence the spin-up of devices, reducing the instantaneous current draw burden when many drives share a power supply. Primarily for use in large RAID setups. This feature is usually disabled and the drive is powered-up in the active mode (see -C above). Note that a drive may also allow enabling this feature by a jumper. Some SATA drives support the control of this feature by pin 11 of the SATA power connector. In these cases, this command may be unsupported or may have no effect.
What makes this so dangerous? To me it looks like you just wont be able to spin it up until next boot. Which isn't a problem for me. I am just looking to shut off my windows drive while I am in Linux.