The most merciful thing in the world is the inability of the human mind to correlate all its contents.
H. P. Lovecraft
256 color terminals

While the rest of the techworld is getting excited about their aero, quartz or compiz 32bit color 3D desktop, I reached a less impressive milestone today:

From now on I use a 256 color terminal ;-). Actually I looked into this earlier, but since gnome-terminal and screen didn't support it back then (maybe upstream, but not in my distro), I enabled support just today.

Excellent documentation on this topic is already available on multiple places, but to summarize for myself:

.screenrc 
attrcolor b ".I"
termcapinfo xterm 'Co#256:AB=\E[48;5;%dm:AF=\E[38;5;%dm'
defbce "on" 
startup_message off

.bash_profile 
set TERM xterm-256color; export TERM

.vimrc 
set t_Co=256 
colorscheme=asudark

For vim you need a special colorscheme (gvim colorschemes do not work). My vim hacked 256 colors scheme, which work better with a transparent background then the original, is available here.

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Posted by jochem on 2008-09-26, last update on 2008-09-26
Ubuntu Hardy Heron

Today I installed Ubuntu Hardy Heron on a desktop computer. I am pretty distro/desktop agnostic (see my ten year anniversary post), but since Debian Etch is a bit old for a desktop and Hardy Heron has Long Term Support (I do not want to update/fix a computer every half year!!) Ubuntu was my choice.

There are unlimited gnome improvements which I don't care about, but some things stand out for me in this release.

So thanks again for all free software developers!

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Posted by jochem on 2008-04-19, last update on 2008-08-29
Helping the environment

A lot of work is done in making linux suspend work better. For me it works perfect (from linux kernel 2.6.20 or so). Therefore I wanted to go a step further and let my class A, heavy power-using receiver switch off when my desktop computer suspends (to ram). And switch back on when my computer wakes up. The motivation is that I only listen music via my computer.

To achieve this I bought the Gembird Silver Shield, a USB-switchable power adapter. I was prepared to do some nice USB snooping and C programming to get this device working in linux, but (un)fortunately there was already a working utility for this device.

Configuration for suspend/hibernate is not so easy and documentation is sparse for the user mode utilities. Since it took me more than the usual googling I will summarize my conclusions here for later use. First the gnome-screensaver measures the idle time. After this timeout is expired the gnome-power-manager starts to measure his own timeout (so before suspend the two times will stack). When the gnome-power-manager times out it will look at the Inhibit flag. If there is no inhibiting (for example my rhythmbox pushes Inhibiting, because I do not want to suspend when music is playing) your computer will suspend.

Since a custom script should be added to switch the power-switch off via usb with sispmctl the suspend-backend is important. Gnome power manager can use multiple backends to go to suspend mode. This works via hal (the hardware abstraction layer). Configuration for this is in /usr/share/hal/information. HAL is responsible for calling the suspend-backend. The default suspend-backend on my machine is pm-utils. (which can be tested with pm-(suspend/hibernate/power-save etc.). I also have a package called hibernate (which can also suspend, confusing isnt' it?). A third one is suspend2 (which can also hibernate....). These backends have different ways of adding custom hooks.

To add a hook to hibernate I added a file called local in /etc/hibernate/scriptlets.d/. The API is as follows (ugly in my book): 

# -*- sh -*-

UsbPowerSocketDown() {
      /usr/bin/sispmctl -f1
}
UsbPowerSocketUp() {
      /usr/bin/sispmctl -o1
}

AddUsbOptions() {
      AddSuspendHook 10 UsbPowerSocketDown
      AddResumeHook 10 UsbPowerSocketUp
      return 0
}

AddUsbOptions

Pm-utils has a much nicer API. To add a custom hook add a file to /etc/pm/sleep.d . This uses init style ordering. So look in /usr/lib/pm-utils/sleep.d/ for a proper number. I needed to talk to the usb-bus AFTER the modules were loaded, so a number lower than 50. So I added /etc/pm/sleep.d/10usbpoweroptions with content like this: 

#!/bin/bash
case $1 in
    suspend)
        /usr/bin/sispmctl -f1 
    ;;
    resume)
        sleep 1
        /usr/bin/sispmctl -o1 
    ;;
esac

After all this fiddling it works like a charm! Now hopefully one standard will emerge; because how to achieve the same result with KDE I don't know. I had to manually patch rhythmbox to change calling (via dbus) the Inhibit method from org.gnome.powermanager to org.freedesktop.powermanagement (because i used a wrong combination of versions..), so this suggests a move in the right direction.

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Posted by jochem on 2008-02-02, last update on 2008-02-02
Qemu/kvm and xorg screen resolution

Fast virtualization is cheap nowadays on linux. Just apt-get install kvm on a recent kernel and VT-enabled processor and you are ready to run all kind of different os-es on your host. No more recompiling the vmware kernel modules *again* or fiddling with xen-modified kernels and difficult networking setups. Yeah!

One problem I encountered was getting a decent resolution (f.g. 1280x1024 or higher) in the guest xserver (xorg). Google was not really helpful this time so therefore I post this note for future reference. Qemu emulates two kind of video cards, standard is a cirrus, -std-vga provides you with a vesa one. Vesa was not able to help me (garbled screen), so using the (default) cirrus emulator is the way to go for a linux guest.

The trick was in changing the monitor sync and refresh rates, autodetection did not work properly (in my centos 4.0 guest). So here is my working snippet of /etc/X11/xorg.conf: 

Section "Device"
  Identifier  "Generic Video Card"
  Driver      "cirrus"
EndSection

Section "Monitor"
  Identifier  "Generic Monitor"
  Option    "DPMS"
  HorizSync 28-64
  VertRefresh 43-60
EndSection

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Posted by jochem on 2007-10-01, last update on 2007-10-01
10 years GNU/Linux

I am using GNU/Linux for 10 years! As a celebration I made a white chocolate cake (recept) with tux on it. Thanks to all the volunteers for this great combination of free software. In the past I have used all major distributions, nowadays I am stuck with Debian. In fact I am rather distro-agnostic, if it runs xterm, screen, vim, mplayer, gcc and mutt I am happy. Pro is the nice Debian philosophy, con the fact that is has not incorporated SElinux yet. So perhaps I will switch in the next 10 years again?

Sidenote for R. Stallman: when i am using gnu/linux 25 years I promise to make a gnu cake :-D.

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Posted by jochem on 2007-09-16, last update on 2007-09-16
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