APM: Disabled vs 254

[pechkin000]

Hi,
I know the idle timeout issue has been discussed a lot but I am not 100% clear, even after reading many threads, on the subject of APM settings. I would like to get a definitive answer on the effect of disabling APM vs setting it at 254. I used WDIDLE3 to disable head parking completely, so I basically want disks spinning continuously, in order to achieve that reliably am I to disable APM or should I be setting it to 254?
Any clarifications would be appreciated.
Thanks

 

[mav@]

According to ATA specifications, drive should never park heads if APM level is set to 128 or higher.

 

[joeschmuck]

Set APM to Disable, by setting APM to anything else you may inject commands you do not desire. APM should override the drive default settings.

 

[pechkin000]

Got it, thanks!