[ltp] what to use to save battery

[linux-thinkpad@linux-thinkpad.org]

Trying to help elaborate some of the points below...

> - a SD Card for the home directory

    I.e., to avoid running your actual hard drive.  Use SD, compact
    flash, a "thumb" or "jump" drive, etc.  The basic principle is
    to use a low-power device (which your hard drive is not) for
    storage.

    If you have a lot of RAM, you could even create a RAM disk for
    your home directory.  Likewise for /tmp and /var.  Although, in
    case of power loss or similar, you do want to have some kind of
    sync'ing to non-volatile storage.

> - use cpufreq

    There's a package, I believe it's called "cpufrequtils" that
    allows you to control the power draw and freqency of your
    processor.  (Note, you have to have the proper kernel config
    options for this to work, but the docs and thinkwiki explain
    this I believe.)

    For example, "cpufreq-set -g powersave" will put your processor
    in it's lowest power state.  I use the "powersave" and
    "conservative" governers most often.

    Your video chipset (especially if it's an ATI) probably also has
    some similar tools for reducing power consumption.  See
    thinkwiki.org for details.

> - use a blank screensaver which disables the display correctly

    Does xscreensaver do this correctly?

> - don't use postfix/exim use ssmtp instead

    I believe these all belong to the class of applications known as
    MTAs, or mail transport agents.

    If I'm not mistaken, postfix and exim are both daemons (meaning,
    running programs that consume CPU/disk/RAM), whereas ssmtp is
    more "reactive", only doing something when it absolutely needs
    to.  Someone check me on this!

> - enable wireless powersaving

    On my wireless, "iwpriv eth1 set_power 7".  I believe the
    manpage for "iwpriv" (part of wireless-tools, I think) will tell
    you how to query your wireless card for what can and cannot be
    tweaked.

Good luck!
Matt