Quite a few people or looking for an answer to this puzzle. I’ve asked around and made a pretty short and clear post on the question in a few places. Now that I’ve found a WD forum I’m trying my luck here ^_^. Here goes:
The main question is actually, what does an OS, system BIOS or RAID-card BIOS need to support staggered spin up?
The hard drive must obviously support some form of power management. The SATA standard seems to revolve around setting pin 11 on the power connector either high or floating. A drive that supports PIUS should then not spin up the motor until asked by the BIOS, OS, … Please refer to the attached PDF called " staggerd-spin-detection-pin11" . Then a PHY command should be issued and voila, the drive will spin up. Rinse and repeat for every drive.
Anyways, that does not seem to work with WD20EADS drives (we all know them). They do support some form of PIUS but call it power management 2 mode (PM2).
Please have a look here http://en.wikipedia.org/wiki/Power-up_in_standby .
- Is this the same as the pin 11 technique?
- Is the pin 11 technique a feature of APM or ACPI?
I do know Areca RAID-controllers don’t play well with these drives and cannot get them out of stand by(I know I can flash them and then they will work but that’s not the scope of my post). One thought from someone was that Western Digital uses ACPI and most vendors use APM to send the wake up command. Areca might not support ACPI thus is unable to wake up the drive.
If someone is wondering why I want staggered spin up: I don’t want to buy a big PSU just to allow the drives to start up. As you know the start up current of hard drives is a lot more than their IDLE/operating power.