[mythtv-users] Putting the Computer to sleep (low-power)

Michael T. Dean mtdean at thirdcontact.com
Sat Jul 30 11:03:08 EDT 2005


Ian Trider wrote:

>On 7/29/05, sammykrupa at comcast.net <sammykrupa at comcast.net> wrote:
>  
>
>>I am running Fedora Core 3 and am looking for instructions on setting-up my computer to go into a low-power mode (not suspend to hard drive) when I am not using MythTV. How would I do this (any links?)?
>>    
>>
>Lucky you, I just found a page about this topic, which seems to be one
>of the Great Mysteries of Linux and one of those things that's always
>irritated me because it's so dead simple to do in Windows and so
>****ing ridiculous under linux. :(
>
>http://www.ma.utexas.edu/users/stirling/computergeek/powersaving.html
>
Did you even read the post you "just found?"  ;)

In my post ( 
http://www.gossamer-threads.com/lists/mythtv/users/141854#141854 ), I 
recommended reading the whole page so people would see just how much 
control you have over power saving in Linux.  Control = options = 
decisions to make.  Windows = all decisions made for you (so hope it 
works the way you need).

Basically, you can tell your hard drive to spin down, but that alone is 
probably not going to do what you want.  Since you're constantly running 
processes on your computer (whether Linux or Windows computers), some of 
those processes--such as logging utilities and journaling filesystems 
and even simply modifying file access times on journaling or 
non-journaling filesystems--require almost constant disk writes.  If you 
don't take that into account and tell your system to modify logging 
parameters when the disk spins down or tell it how and when to flush 
buffers to disk or to ignore writing access times to the filesystem, you 
could even get higher power usage with the spin-down than without.

On Linux, you can explicitly power off the monitor with software (as 
opposed to setting a timeout on a screensaver and waiting), explicitly 
throttle the CPU (as opposed to letting it scale performance based on 
usage--which, TTBOMK, is the only option for AMD in Windows; whereas 
Intel only uses the lowest CPU speed when on battery), and--as implied 
above--control usage of the disk.  When appropriate decisions for each 
of these (and other power saving methods) is made, you can maximize 
power savings for your particular usage of the system (no two systems 
are used exactly the same way).

On Windows, however, you have no control over these and many other 
settings.  Windows seems to read the disk whenever it gets bored, and 
you have to trust that Microsoft decided that disk access was really 
necessary.  You have to assume that Microsoft chose the best way to 
control all the power settings for you.  Since there are maybe 5 
settings (things like "Best Performance" and "Maximum Power Savings", 
IIRC), then I'm sure they've chosen the perfect settings for at least 5 
people out there...

Sorry for the rant.  I just see so many people pining for "Microsoft 
Linux" anymore, I feel its important to note the difference.  If you 
really want someone to make all the decisions for you, go with Windows 
(that's exactly why I have never recommended any friends, family, or 
acquaintances switch to Linux--they don't want or need to know how or 
why or have any reason to control any of it, they just want it to 
work).  If you want control over your hardware and software, Linux is 
the way to go.

Mike


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