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Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

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Cache rewrite.

Extending OpenSSH.

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Extending Battery Life on X60 (OpenSuse, powertop)

From: "andrew cooke" <andrew@...>

Date: Sat, 29 Nov 2008 17:46:47 -0300 (CLST)

I just bought a new battery and decided to see if I could extend its life
by careful configuration of my system.  Typically I use my laptop plugged
into the mains at home, and so don't need a battery except if I'm carrying
it from one room to another.  The only time I really rely on the battery
is when I am flying, and then typically I want to get some work done, but
have no need for sound or an internet connection.

So what follows is a bit extreme, perhaps, because I only intend to use it
when, for example, on an aeroplane.

First, I disabled 3d acceleration on the graphics (this is a checkbox
inside SAX - if you go to the Yast GUI thing for the display you'll see
it).  That has made the fonts uglier (and smaller) for some reason.

Second, I run the following script as root immediately after booting (by
hand, once I have logged in).

Together, that lowers the number of interrupts to the low 10s per second
(this is the number that the powertop tool focuses on - it means that the
CPU can stay in its idle state for longer).

Andrew

PS Here's the script - it's quite possible that some things are
unnecessary; I just kept piling stuff on until the numbers went down...

#!/bin/bash

/etc/init.d/mysql stop
/etc/init.d/powersaved stop
/etc/init.d/ntp stop
/etc/init.d/sshd stop
/etc/init.d/network stop

ifconfig wlan0 down
ifconfig eth0 down

mount -o remount,noatime /

echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
ethtool -s eth0 wol d

killall NetworkManager
killall gaim
killall kopete
killall synergyc
killall skype
killall kaffeine
killall gkrellm
killall artsd
killall kpowersave
killall kpowersaved
killall knetworkmanager
killall kmix
killall klipper
killall acpid

for module in thinkpad_acpi pcmia yenta_socket snd_pcm_oss snd_seq
snd_seq_device snd_hda_intel snd_pcm snd_timer snd_hwdep snd_mixer_oss
snd_page_alloc snd processoracpi_cpufreq ehci_hcd uhci_hcd usbcore e1000e;
do
  echo "$module"
  if `lsmod | grep "$module"`; then
    rmmod "$module"
  fi
done

Font Size

From: "andrew cooke" <andrew@...>

Date: Sat, 29 Nov 2008 17:59:07 -0300 (CLST)

The font size changed because somehow Sax decided the monitor was 15". 
You can fix that by: Yast -> Hardware -> Graphics Card and Monitor (this
is where the Activate 3d Acceleration option is) -> Change -> Display Size

Andrew

Batter Control via SMAPI

From: "andrew cooke" <andrew@...>

Date: Sun, 30 Nov 2008 08:43:50 -0300 (CLST)

To improve battery life (how long before I need to buy another) I started
looking at the recharge pattern.  You can configure this in windows via
the Lenovo power management tool.  In Linux you need to install tp_smapi.

tp_smapi is described here - http://www.thinkwiki.org/wiki/Tp_smapi

You can download it here - http://sourceforge.net/projects/tpctl/

Check Yast to make sure you have the kernel source installed.

It's easy to install:
 tar xvfz ../archive/ibm/tp_smapi-0.39.tgz
 cd tp_smapi-0.39/
 sudo make install
 sudo modprobe -a tp_smapi
 sudo bash -c "echo 'install tp_smapi /bin/true' > /etc/modprobe.conf.local"

Then everything is accessible via a sysfs interface:
 ls /sys/devices/platform/smapi/
In particular:
 sudo bash -c "echo 80 >
/sys/devices/platform/smapi/BAT0/start_charge_thresh"
or whatever number you want...

It's not clear to me how persistent this value is, or whether it is
necessary to do this in Linux if you dual boot Windows.  My only data
point is that I set a value of 90 in Windows and that appeared when I
installed this module in Linux immediately afterwards.  That would suggest
only one is necessary, and that it is permanent.

Andrew

PS This will work for many thinkpad batteries on Linux (I am using
opensuse 11) - it's not just X60.

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