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0e1f616
(Get the code!)
to Bart Samwel :
Thanks for all your help in solving this problem. Having acpi-support setting some sane apm default while on battery and 254 while on AC would be a big help to solve this problem.
Possible problems with a default apm of 128 while on battery :
* some people might use their laptops *a lot* on battery. People who use their laptops for 9 hours a day and are seeing a Load_Cycle_Count increase of more 60 per hour will reach 600.000 Load_Cycles within three years of usage. The amount of people who would use their laptop for 9 hours each day are probably a very small minority. Using the laptop on battery for more than 9 hours a day increases the risk of bumps *a lot* which would make using apm 254 a sure harddrive killer. Their battery would probably be dead way before their harddrive dies. Some of these people might also prefer flash disks which don't have moving parts.
* Some users would use their laptop on battery for four hours each day. They would have a problem if their Load_Cycle_Count would increase with more than 136 per hour.
* If most people would run on battery for seven hours a week they would be able to handle 549 Load_Cycles per hour and still not reach 600.000 Load_Cycles within three years of usage.
* some people already have a really high Load_Cycle_Count because they have been using aggressive power management defaults set by their harddrive even while on AC. They would have to manually override this number of 128.
Possible problems with a default apm of 254 while on battery :
* no protection from bumps making it more likely for the harddrive to die from an accidental bump. The more you use your laptop on battery the higher the risk of death by bump.
* more power usage
Maybe some value between 128 and 254 works better for running on battery. The problem is that apm values between 128 and 254 are different for each harddrive and might even turn off head parking for some drives (as I understand it). If an apm of 253 would guarantee a "low amount of head parking but still do some headparking" that might be a more sane default for running on battery but as far as I know it doesn't (but I'm not an expert).
IMHO all of this makes very clear that reducing unnecessary disk activity is also very important.