ndap.net

Mounting encrypted USB disks in GNOME

ndap — 2008-09-13T00:16:48+02:00

I keep my backups on a encrypted partition (LUKS format) on an external USB-drive. When I connect it GNOME displays a password dialog which often, but not always, leads to my backup partition being mounted.

I have gotten very careful in entering the password so I am fairly sure that it is due to a bug in the version of gnome-mount that is in Debian Lenny. A workaround is to open gnome-terminal and entering

$ gnome-mount --disconnect-crypto -d /dev/sda2
$ gnome-mount -d /dev/sda2

If that doesn't work the following should:

$ gnome-mount --disconnect-crypto -d /dev/sda2
$ pmount /dev/sda2

(Don't forget to replace /dev/sda2 with whatever is appropriate for you.)

fetchmail via SSH tunnel

ndap — 2008-02-09T19:14:13+02:00

If you have SSH access to your mail server, fetchmail can automatically create a secure SSH tunnel through which to retrieve email. Use the preconnect configuration option in ~/.fetchmailrc:

poll localhost service PORT with proto POP3
  password "secretpass"
  preconnect 'ssh -f -C -L localhost:PORT:localhost:REMOTEPORT
              USERATHOST sleep 3 < /dev/null > /dev/null'

The preconnect option should be on a single line. Replace PORT, REMOTEPORT, and USERATHOST with your own values.

PORT: The port number on your own desktop or laptop computer that fetchmail should connect to.
REMOTEPORT: The port on the mail server which we want to connect to. For a POP3 server it is port number 110.
USERATHOST: User name and hostname that SSH shall use to connect to the mail server. Example: username@my.mailserver.com
sleep 3: A command for SSH to run on the remote host. SSH will disconnect when the command has run. (sleep 3 gives fetchmail time to connect to the remote mail server. SSH will notice that the forwarded port is used and won't disconnect until fetchmail has finished.)

Saving disk space by removing unwanted translations

ndap — 2008-01-18T21:43:19+02:00

There is an easy way to free about 10% of the used disk space under /usr. Most (all?) packages in Debian ship with translations for a large number of languages. On a personal computer with only one or a couple of users there's usually only need for a single language, so why not delete all the unneeded translations to free up some space on /usr?

Install the localepurge packet, select which languages you want to keep, and localepurge will automatically remove all other translations every time you install or upgrade a package.

As localepurge does not remove existing translations after the installation, you need to run

$ localepurge

manually as root.

Note: localepurge has worked fine for me on several machines, but not everyone has been as lucky.

For more information on internationalisation (i18n for short) and localisation in Debian, visit the homepage of the Debian i18n Task Force.

Suspend to RAM on Debian Etch and IBM Thinkpad X31

ndap — 2007-04-23T22:31:01+02:00

Seems like my machine (Thinkpad X31 with ATI Radeon Mobility M6 LY) locks up when resuming from suspend-to-RAM unless I comment out the line

VbeToolPost yes

in /etc/hibernate/ram.conf. Regular hibernation to disk works fine out of the box though.

Bug filed on the Debian hibernate package.

CPU frequency scaling in Debian 4.0 Etch

ndap — 2007-04-23T15:04:10+02:00

Apparently there is a more "correct" way to enable CPU frequency scaling in Debian 4.0 GNU/Linux Etch than I described in an older post.

For future reference:

$ echo speedstep_centrino >> /etc/modules
$ echo cpufreq_conservative >> /etc/modules
$ echo ibm_acpi >> /etc/modules

$ apt-get install cpufrequtils

Then edit /etc/defaults/cpufrequtils to read:

ENABLE="true"
GOVERNOR="conservative"

Swedish mistranslation in Google Search

ndap — 2007-04-22T14:39:57+02:00

Noticed a new link today when searching on Googles swedish site. It read Mina bärbara datorer (eng. My Laptops). I wondered how Google could know I was using a laptop, but upon following the link it turned out to be a new note-taking function. The error is probably due to a machine translation of My notepads.

Though bärbara datorer can be a correct translation for notepads in other contexts, in this case Google should use anteckningsblock instead.

Etch post-install on IBM Thinkpad X31

ndap — 2007-04-21T17:02:32+02:00

Some useful things to do after installing Debian GNU/Linux 4.0 "Etch" on an IBM Thinkpad X31.

Activate CPU frequency scaling to conserve power and get rid of fan noise:

$ echo speedstep_centrino >> /etc/modules
$ echo cpufreq_conservative >> /etc/modules
$ echo ibm_acpi >> /etc/modules

$ apt-get install sysfsutils
$ echo "devices/system/cpu/cpu0/cpufreq/scaling_governor = conservative" \
    >> /etc/sysfs.conf

Get access to more capable multimedia packages by adding a Debian Multimedia mirror to the file /etc/apt/sources.list. Then:

$ apt-get install debian-multimedia-keyring

Install tpb for on-screen display of sound volume and TFT brightness. All desktop users has to be added to the nvram group.

$ apt-get install tpb
$ adduser username nvram