John's Blog

Hitting something with a hammer often feels good but does nothing useful. Here's one case where it actually helps. On my 2004 Ford Explorer the alternator light came on. I brought it to the auto parts store and they put a volt meter on it. The alternator needs to put out a voltage that is higher than the battery's full charged voltage in order to properly function - somewhere in the 14 volt range. Mine came in low - probably below 13.5 volts. So the guy at the auto parts store took a rubber mallet to the alternator and just briefly, for a period of 10 seconds or maybe less the voltage jumped up into the normal range before falling back to where it was before. This confirmed the diagnosis of a bad alternator in general and worn brushes in particular. The brushes are spring loaded, are located in the are a wearable item and must make contact with the fixed part of the alternator. Tapping the alternator with the hammer temporarily changes spatial relationships between the brushes ...

The web interface for 3ware's RAID controller, 3dm2 uses a self signed certificate when you connect via https://localhost:888.  Firefox and Chrome will not accept such a certificate (even if you configure a "security exception), so you cannot administer your RAID controller via the web interface.  All you get is a "connection reset" screen. (tw_cli and BIOS utility still work, however). Someone on the web suggested using the Konqueror browser and sure enough this worked. You still need to create a security exception in Konqueror, but once that is done you can get back to your 3dm2 web interface.

Why would anyone want to swap left and right pulseaudio channels? After some web searching I found that I am hardly alone. The classic problem is that your computer is on one side or the other, the audio-in cable goes to one speaker or the other, and the audio cable is too short. But this is linux, after all, so most things if not all things are possible, right? The first fix I came across was simple enough except sadly it didn't work. This called for editing /etc/pulse/deamon.conf and uncommenting the lines ; default-sample-channels = 2 ; default-channel-map = front-left,front-right to appear as default-sample-channels = 2 default-channel-map = front-right,front-left and then restarting pulseaudio with pulseaudio -k Seemed very clean and elegant except that it didn't work. :( The next answer from  here  and this worked great. The steps (reproduced here) are: cat /proc/asound/cards and use the name string for the device you wish to use (the one in squ...

As indicated now in the title of Redhat Bugzilla 969648 the problem is the "data=writeback" parameter in /etc/fstab. Fedup and Fedora 19 have a problem with this particular setting.  I have two fedora machines - a desktop and a laptop. During the last upgrade cycle, Fedora 17-->18, the desktop upgraded without any problem whatsoever. On the laptop, I had managed to shoot myself in the foot due to basically having some parts of my kernel boot commandline that were present in grub.cfg but not in /etc/default/grub. (These were the parts that blacklisted nouveau so that the nvidia binary driver could run). At the end of the fedup procedure I had run     grub2-mkconfig -o /boot/grub2/grub.cfg as instructed and this wiped out the parts of my command line that were needed to run the nvidia driver and due to that I had all sorts of problems figuring out the problem. Of course once the problem was diagnosed the fix was relatively easy. This time around, in going from 1...

I've recently been writing some homegrown scripts to parse web pages and do something useful with the information using Python 2.7 and the BeautifulSoup library.  This involves printing the output to a terminal (e.g. Gnome Terminal) where the output is hopefully human readable but in some cases was not. The most common issue I ran into were various forms of "smart quotes" and similar html annoyances. If this is not properly handled you'll get output like John X s Blog (where X is the following 7 character group without the intervening spaces - hard to display it verbatim in the blogger environment!)  & # 8 2 1 7 ;  or even John X s Blog   (where X is some awkward block symbol that can't be adequately described or rendered here. This actually results from the MS quote being "decoded" as Latin-1 - so it's sort of a cascade of errors.) The first of these is known as an "HTML entity" and here is a list of them .  ...

Google recently rolled out a new version of their Google Maps web service. From what I can tell you can't retrieve a set of GPS coordinates from the new interface. I expect they will remedy that situation at some point.  But for now the workaround is to temporarily switch back to "Classic" Google maps and get the GPS coordinates from there. Here's what I did: Shift back to Classic maps (Gear in top right corner, choose Classic Maps, can say "Dismiss" to not make the switch permanent if desired). Right click on desired location and select "What's Here?" A green arrow will appear. Left Click on Green Arrow and  the  GPS   coordinates will appear in multiple locations.

Did a yum update with Fedora 18 and got nothing but timeouts and 404 not found errors.  yum clean metdata      and yum clean all      and (a reboot) were all of no help. However yum --disableplugin=fastestmirror update completely fixed the problem. Trying other mirror. http://mirror.nexcess.net/rpmfusion/nonfree/fedora/updates/18/x86_64/repodata/8b5178f2b98050e518752afe8fbe527c4d7a53bde138a7f3ce276766ec71869e-comps.xml.gz: [Errno 12] Timeout on http://mirror.nexcess.net/rpmfusion/nonfree/fedora/updates/18/x86_64/repodata/8b5178f2b98050e518752afe8fbe527c4d7a53bde138a7f3ce276766ec71869e-comps.xml.gz: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds') Trying other mirror. http://mirror.liberty.edu/pub/rpmfusion/nonfree/fedora/updates/18/x86_64/repodata/8b5178f2b98050e518752afe8fbe527c4d7a53bde138a7f3ce276766ec71869e-comps.xml.gz: [Errno 12] Timeout on http://mirror.liberty.edu/pub/rpmfusion/nonfree/f...