External usb hdd WD Elements - avoid spindown -- #2

A little update regarding the USB HDD spin-down-problem (discussed here: External usb hdd WD Elements - avoid spindown).
I found a better workaround somewhere (sorry to the original author - i forgot where...).

By default, the APM_level is set to 96(d) (60h) after every reconnect.
When setting this value to 128(d) (80h), the drive spins down after .. approx. 30-45 minutes (i haven't tested this exactly, but it definitely doesn't spin after.. lets say 1h).

The APM_level can be set with hdparm:

# hdparm -B /dev/disk/by-label/WD_500G_NTFS
/dev/disk/by-label/WD_500G_NTFS:
APM_level = 96

# hdparm -B 128 /dev/disk/by-label/WD_500G_NTFS
/dev/disk/by-label/WD_500G_NTFS:
setting Advanced Power Management level to 0x80 (128)
APM_level = 128

Note: The hard disk doesn't remember this setting. Like written before - after every reconnect it has its default setting of 96d.


Update1 / additional information:
The hdparm method works for me on the following Kernel:

$ uname -s -r -v -o
Linux 3.0.0-1-686-pae #1 SMP Sat Aug 27 16:41:03 UTC 2011 GNU/Linux

but on

uname -s -r -v -o
Linux 3.1.0-1-686-pae #1 SMP Mon Nov 14 08:24:20 UTC 2011 GNU/Linux

i get the following error when running hdparm:

# hdparm -B /dev/disk/by-label/WD_500G_NTFS
/dev/sdb:
HDIO_DRIVE_CMD(identify) failed: Invalid argument

edit1: (17.12.2011)
-added information regarding different kernel versions.