Rockbox General > Rockbox General Discussion
ipod 5.5g Sleep mode?
AlexP:
My point is solely that we don't know one way or another so saying things like:
--- Quote from: grawp on September 15, 2007, 07:36:19 PM ---
--- Quote from: silentseraph on September 15, 2007, 05:20:26 PM ---well, i mean, thats the point of sleep mode. It doesnt eat up a lot of battery, but its still "on". It just kills the battery to boot it up again and again, and while in school, ill have to turn it off in between classes, which kills it a lot faster than it would If I could put it to sleep. Im not saying that leaving it off takes more power, but booting it up repeatedly just kills it really fast.
--- End quote ---
you're definitely right. :)
--- End quote ---
is meaningless.
This is all a bit academic, seeing as we don't know the hardware well enough to initialise everything properly so we don't use so much battery when running properly, let alone sleep components.
silentseraph:
Ive done some research and for the type of hard drive the 5g ipod video uses (toshiba MK3008GAL) there is a large (i dont really know power measurements though) difference in the amount of energy required to start up and to sleep
http://sdd.toshiba.com/main.aspx?Path=HardDrivesOpticalDrives/1.8-inchHardDiskDrives/MK3008GAL/MK3008GALSpecifications
heres the page and if you scroll down to power consumption you see that starting up the hard drive requires 1.8 watts of energy while sleeping requires a considerably smaller amount (only .07 watts of energy)
GodEater:
But the 0.7 watts of energy whilst sleeping is a *constant* drain - whilst spinning up is a one off.
AlexP:
--- Quote from: silentseraph on September 17, 2007, 04:32:20 AM ---Ive done some research and for the type of hard drive the 5g ipod video uses (toshiba MK3008GAL) there is a large (i dont really know power measurements though) difference in the amount of energy required to start up and to sleep
http://sdd.toshiba.com/main.aspx?Path=HardDrivesOpticalDrives/1.8-inchHardDiskDrives/MK3008GAL/MK3008GALSpecifications
heres the page and if you scroll down to power consumption you see that starting up the hard drive requires 1.8 watts of energy while sleeping requires a considerably smaller amount (only .07 watts of energy)
--- End quote ---
Yes, of course. I'm not saying sleep isn't useful in some circumstances, I'm just saying without measuring numbers you cannot make sweeping statements like you originally did. Without measurements, we have no way of knowing the cut off point. I seem to remember back in the day someone did just such a measurement for an Archos device, and concluded about four minutes was the cutoff point between it being worth turning off and not. This was between sitting idle and turning off, and doesn't apply to the different hardware of the iPod anyway, but again:
My point is not that in some circumstances sleep cannot save power, it can. My point is only that you do not know those circumstances without measurements. Is it five minutes, is it ten minutes, is it an hour, is it a day?
Llorean:
Also: 0.07 watts for 90 seconds is more energy than 1.8 watts for 3 seconds. So we'd need to still know how long this "start" drain takes place over, and how long the drive sleeps.
Seriously, if shutting down the drive was energy inefficient, why do you think battery life *increases* when we enable HD power off?
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