| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next


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.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

Last 100 entries

Brandalism; Table of Shifter, Cassette and Derailleur Compatability; Lenovo Demonstrates How Bad HTTPS Is; Telegraph Owned by HSBC; Smaptop - Sunrise (Music); Equation Group (NSA); UK Torture in NI; And - A Natural Extension To Regexps; This Is The Future Of Religion; The Shazam (Music Matching) Algorithm; Tributes To Lesbian Community From AIDS Survivors; Nice Rust Summary; List of Good Fiction Books; Constructing JSON From Postgres (Part 2); Constructing JSON From Postgres (Part 1); Postgres in Docker; Why Poor Places Are More Diverse; Smart Writing on Graceland; Satire in France; Free Speech in France; MTB Cornering - Where Should We Point Our Thrusters?; Secure Secure Shell; Java Generics over Primitives; 2014 (Charlie Brooker); How I am 7; Neural Nets Applied to Go; Programming, Business, Social Contracts; Distributed Systems for Fun and Profit; XML and Scheme; Internet Radio Stations (Curated List); Solid Data About Placebos; Half of Americans Think Climate Change Is a Sign of the Apocalypse; Saturday Surf Sessions With Juvenile Delinquents; Ssh, tty, stdout and stderr; Feathers falling in a vacuum; Santiago 30m Bike Route; Mapa de Ciclovias en Santiago; How Unreliable is UDP?; SE Santiago 20m Bike Route; Cameron's Rap; Configuring libxml with Eclipse; Reducing Combinatorial Complexity With Occam - AI; Sentidos Comunes (Chilean Online Magazine); Hilary Mantel: The Assassination of Margaret Thatcher - August 6th 1983; NSA Interceptng Gmail During Delivery; General IIR Filters; What's happening with Scala?; Interesting (But Largely Illegible) Typeface; Retiring Essentialism; Poorest in UK, Poorest in N Europe; I Want To Be A Redneck!; Reverse Racism; The Lost Art Of Nomography; IBM Data Center (Photo); Interesting Account Of Gamma Hack; The Most Interesting Audiophile In The World; How did the first world war actually end?; Ky - Restaurant Santiago; The Black Dork Lives!; The UN Requires Unaninmous Decisions; LPIR - Steganography in Practice; How I Am 6; Clear Explanation of Verizon / Level 3 / Netflix; Teenage Girls; Formalising NSA Attacks; Switching Brakes (Tektro Hydraulic); Naim NAP 100 (Power Amp); AKG 550 First Impressions; Facebook manipulates emotions (no really); Map Reduce "No Longer Used" At Google; Removing RAID metadata; New Bike (Good Bike Shop, Santiago Chile); Removing APE Tags in Linux; Compiling Python 3.0 With GCC 4.8; Maven is Amazing; Generating Docs from a GitHub Wiki; Modular Shelves; Bash Best Practices; Good Emergency Gasfiter (Santiago, Chile); Readings in Recent Architecture; Roger Casement; Integrated Information Theory (Or Not); Possibly undefined macro AC_ENABLE_SHARED; Update on Charges; Sunburst Visualisation; Spectral Embeddings (Distances -> Coordinates); Introduction to Causality; Filtering To Help Colour-Blindness; ASUS 1015E-DS02 Too; Ready Player One; Writing Clear, Fast Julia Code; List of LatAm Novels; Running (for women); Building a Jenkins Plugin and a Jar (for Command Line use); Headphone Test Recordings; Causal Consistency; The Quest for Randomness; Chat Wars; Real-life Financial Co Without ACID Database...; Flexible Muscle-Based Locomotion for Bipedal Creatures; SQL Performance Explained

© 2006-2013 Andrew Cooke (site) / post authors (content).

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).


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...


/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;
  echo "$module"
  if `lsmod | grep "$module"`; then
    rmmod "$module"

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


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 >
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.


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

Comment on this post