Author: halfgaar (Page 7 of 26)

Halfgaar is Wiebe. Wiebe is a contributing author on this weblog. He also has a lot of stuff (such as long, in-depth articles) on his personal website.

Wiebe's day job is as a senior software developer and system administrator at YTEC.

In his free time, he built the free, open-source FlashMQ software. Together with Jeroen and Rowan, he is now building a managed MQTT hosting business around his open masterpiece.

Disabling http(s) trimming from Firefox address bar

March 24, 2013 / halfgaar

Some time ago, the Firefox developers decided it was a good idea to trim the http(s):// from the address in the address bar. Since then, I’ve been getting HTTPS site where I don’t want it, because I can’t see what I’m doing. Especially so because HTTPS has no concept of virtual host names, and putting https:// in front of any domain might put you on a completely different web site. So, when I accidentally typed https:// in front of an URL once, it will remember that, but not show me…

Luckily it can be disabled, by setting browser.urlbar.trimURLs to false in about:config.

This annoying feature is right up there with the removal of the RSS icon from the address bar.

Cheap Logitech USB video webcam

March 20, 2013 / halfgaar

Noting this down to not forget.

The Logitech HD Webcam C270 is a cheap webcam that is simply a USB video device, so it works in all OS’s without special drivers.

20×2 LCD display

March 11, 2013 / halfgaar

There are a million 20×2 characters LCDs out there, but this is one that I like:

http://www.okaphone.com/artikel.asp?id=475234
Farnell code: 9448780

It has a metal frame that fits my cross-over front panel, and the metal frame is shiny silver. And, the screw holes aren’t grounded.

Making my USB webcam not the first sound card

March 4, 2013 / halfgaar

When I booted my system with the webcam plugged in, it was sound device 0, instead of 1. This is annoying, so I added this to /etc/modprobe.d/alsa.conf:

options snd slots=,snd_usb_audio

This forces the usb sound module to take second place.

Creating a Xen bridge with bonding on Debian

March 1, 2013 / halfgaar

Like this, but then with bonding:

# The loopback network interface
auto lo
iface lo inet loopback
 
auto bond0
# The primary network interface
iface bond0 inet manual
  slaves eth0 eth1
  bond-mode active-backup
  bond-miimon 100
  bond-downdelay 200
  bond-updelay 200
 
auto xenbr0
iface xenbr0 inet static
  address 1.2.3.4
  netmask 255.255.255.0
  network 1.2.3.0
  gateway 1.2.3.4
  dns-nameservers 1.2.3.4 5.6.7.8
  bridge_ports bond0
  bridge_fd 0

I needed it because I had have a dedicated server that was setup with ethernet bonding that I wanted to install Xen on. Normally, you can let xen setup the network with “network-script network-bridge” in /etc/xen/xend-config.xsp, but that doesn’t work when you have bonding. And, it’s actually better to do it with Debian’s netconfig anyway.

A new Archlinux upgrade, a new unbootable system

February 15, 2013 / halfgaar

It’s that time again…

First my grub broke. So I had to type my config manually:

root (hd0,0)
kernel /vmlinux26 root=/dev/mapper/lvmopraid-root
initrd /kernel26.img
boot

Then my logical volumes can’t be found. Type this in the recovery shell:

lvm lvchange -a e lvmopraid

I commented on an archlinux bug about this.

And then nothing started anymore on boot, because everything is migrating to systemd (as opposed to systemv), without telling me… Still working on fixing that.

Making a bash script terminate when a command returns an error

January 21, 2013 / halfgaar

#!/bin/bash -e
 
trap "echo ERROR HANDLING HERE." ERR
echo "Starting" 
asdfasdf
echo "End"

And when you run it:

Starting
piet.sh: line 5: asdfasdf: command not found
ERROR HANDLING HERE.
End

Chemical tin for circuit boards

January 20, 2013 / halfgaar

For the record, about chemical tin PCB treatment:

Seno Glans Tin

Making Linux less dumb about failed DNS servers

December 28, 2012 / halfgaar

Whenever one of the servers in /etc/resolv.conf is unreachable, Linux/glibc/whatever isn’t smart enough not to retry it for a while. This results in a lot of services becoming unavailable, because a lot of them do reverse lookups on all incoming connections (like SSH), which will hang for the time-out of the first DNS server query.

There doesn’t seem to be a solution, but I worked around it a little bit by putting this in /etc/resolv.conf (or /etc/resolvconf/resolv.conf.d/base && resolvconf -u):

options timeout:2 rotate

Still not perfect, but more workable.

Some links about Macbook sleep problems

December 20, 2012 / halfgaar

My wife’s macbook sometimes keeps waking up when you close it; it gets stuck in an endless sleep-wakeup loop. Here are some links about it that I’ve had in my e-mail forever:

Apple forum discussion

Maintain tool

The problem had to do with Bluetooth, apparently.