Originally Posted by
anon
Revisiting this thread too, to post new information.
It seems Toshiba 2.5" disks also have this "feature". Although it is not as aggressive as Western Digital's nor does it cause lags, I don't want to think my disk is actively wearing itself out every time I use my computer.
The 1 TB external disk I got as a present last year and the one in my new laptop are both of that same brand. Setting the APM value to 255 doesn't work on these, it resets itself back to 127. You have to set it to 254 instead. To accomplish this, use the hdparm fork mentioned in the first post for internal drives, and HDDScan 3.x for external ones.
In the latter case, an additional measure must be taken. The USB-to-SATA adapter seems to do power management as well, so you need to write something to disk regularly to keep it active. Drop the following batch file on its root and keep it running as long as it's plugged in:
Somewhat ugly, but it works.