It's incredibly hard to say because the summary doesn't provide enough detail in and of itself to diagnose the problem (e.g. which graphics card, which chipset, which drivers are being used, which version of Ubuntu and so on). The most likely explanation is that hardware is being left on in Linux that other OSes are powering down when on battery. Examples of this:
Wired ethernet ports that are often put into some off state under Windows such that they will no longer work until the laptop is plugged into the mains but saving power while not in use while on the battery.
Similarly if the poster is using a particular graphics drivers (free or closed - depends on the hardware) they may not be powering the hardware down as aggressively as the drivers on another operating system. I've seen Intel graphics cards on Windows that reduce display quality presumably to increase compression (you can visibly see the artifacts) when on battery to decrease power draw.
Hard disks might not be spun down as often (or at all) under Linux.
USB sockets may not be auto suspending depending on the version of the distro/hardware.
The tickless kernel [lesswatts.org] may not be working effectively (or at all depending on kernel version) - there might be a program that is preventing the kernel from idling for a long period of time because it is doing some unnecessary program (this may tie back into graphics drivers again).
The SATA controller might not be powering down as it does on other OSes.
The screen might not be as dim as it is on other OSes.
The sound hardware might not be powering itself off properly/completely.
The wifi might be be being put into a low power mode/being turned off on other OSes.
There could be bugs in a driver under Linux.
Other OSes might have a program monitoring temperature sensors and scaling hardware functions appropriately (e.g. slowing down fans if the machine is cool).
And so on...
As you can a myriad of reasons and not nearly enough information to whittle down the cause. Further how do you know each OS is using the same defaults? It could be that Windows says you are running out of battery later than Linux does (I'd imagine that this sort of thing could only account for 10 minutes difference to actual empty battery though) or the display is defaulting to a different brightness - it could be that lots of little things are adding up to the major difference.
A few years ago I had access to a Thinkpad T60 and it would draw two watts less power under Windows XP than under Ubuntu Gutsy [ubuntu.com]. That doesn't mean things don't change over time but nor does it mean that people aren't seeing real problems now. If you know how to constructively help, things can get progressively better on your system but it can take some time and you need to know how to track these things down. Tools like powertop [lesswatts.org] help and developers have been putting together good power management practices for Linux guides [codon.org.uk]. However in all honesty posting to Slashdot is unlikely to help you obtain a solution (and indeed there is no guarantee of a solution even over a long period of time).
Hard disks might not be spun down as often (or at all) under Linux.
I was under the impression that modern thinking was that spinning down hard drives was bad for power consumption (presumably due to the vanishingly small power requirements of keeping the disk spinning, vs. the relatively large power requirements of spinning it back up)?
If the disk is powered off for many minutes (for example ten minutes) then the savings compared to the cost of spin up will be substantial (it looks like the pay off starts at around 10 seconds after the hard disk has been put to sleep if you read what is written in Extending Battery Life with Laptop Mode [linuxjournal.com]). It may even be possible to sleep the disk for longer if everything the user needs is cached (e.g. listening to music sequentially with a big buffer). The killer is that all all those spin ups and spin do
It was pity stayed his hand.
"Pity I don't have any more bullets," thought Frito.
-- _Bored_of_the_Rings_, a Harvard Lampoon parody of Tolkein
no solutions? (Score:1)
So it seems the posts here are telling this person to use a different method to watch the movie.
the question remains, why is Linux sucking up batteries at 2,3 times the rate of OS X and even Windows XP ?
Probably leaving hardware on (Score:3, Insightful)
It's incredibly hard to say because the summary doesn't provide enough detail in and of itself to diagnose the problem (e.g. which graphics card, which chipset, which drivers are being used, which version of Ubuntu and so on). The most likely explanation is that hardware is being left on in Linux that other OSes are powering down when on battery. Examples of this:
As you can a myriad of reasons and not nearly enough information to whittle down the cause. Further how do you know each OS is using the same defaults? It could be that Windows says you are running out of battery later than Linux does (I'd imagine that this sort of thing could only account for 10 minutes difference to actual empty battery though) or the display is defaulting to a different brightness - it could be that lots of little things are adding up to the major difference.
A few years ago I had access to a Thinkpad T60 and it would draw two watts less power under Windows XP than under Ubuntu Gutsy [ubuntu.com]. That doesn't mean things don't change over time but nor does it mean that people aren't seeing real problems now. If you know how to constructively help, things can get progressively better on your system but it can take some time and you need to know how to track these things down. Tools like powertop [lesswatts.org] help and developers have been putting together good power management practices for Linux guides [codon.org.uk]. However in all honesty posting to Slashdot is unlikely to help you obtain a solution (and indeed there is no guarantee of a solution even over a long period of time).
Re: (Score:2)
Hard disks might not be spun down as often (or at all) under Linux.
I was under the impression that modern thinking was that spinning down hard drives was bad for power consumption (presumably due to the vanishingly small power requirements of keeping the disk spinning, vs. the relatively large power requirements of spinning it back up)?
Depends on how long the disk is powered down for (Score:1)
If the disk is powered off for many minutes (for example ten minutes) then the savings compared to the cost of spin up will be substantial (it looks like the pay off starts at around 10 seconds after the hard disk has been put to sleep if you read what is written in Extending Battery Life with Laptop Mode [linuxjournal.com]). It may even be possible to sleep the disk for longer if everything the user needs is cached (e.g. listening to music sequentially with a big buffer). The killer is that all all those spin ups and spin do