Fedora 18, WebEx, Java and sound...

I just tried to use WebEx in order to participate in a conference and I was unable to do so. There are a lot of different pages on the Internet that show you what to do. In the end, everything boils down to the fact that WebEx doesn't support 64-bit versions of Linux so all the solutions actually describe how to install 32 bit version of Firefox and Java. Some of those recipes uninstall 64-bit versions of Firefox/Java, some install them in addition to the existing ones. I think the second approach is better, and here is an example of the latter approach.  Note that there isn't problem with sound in Java thanks to the transparent support of ALSA applications by PulseAudio so there is no need to do something like this.

What I found by reading all the recipes is that they assume two things that might catch you:

1. Sun's Java is installed somewhere in the /opt directory. In case you used RPM archive, it will be in /usr/java.
2. People hardcode Java versions, e.g. 1.6.0_21. I don't know why they don't use /usr/java/latest or /usr/java/default because those are valid links on all installations.

In the end I gave up on trying to make WebEx work. Maybe I'll return to it some day and then I'll extend this post...

yum and fastestmirror plugin...

Few hours ago I lost my nerves because when I started yum to update my system, download was painfully slow, somewhere around 20kB/s. It is outrageous because I was using 100 Mbps link and that is probably the slowest link in the chain that ends up somewhere in GEANT. Thus, things have to be much faster than that! The best speed that can be achieved is somewhere around 50Mbps and what I was getting wasn't even remotely close to it! This wasn't something I was prepared to accept as is, so I decided to see what's happening.

Yum has a plugin, fastestmirror. The purpose of that plugin is to determine the fastest available mirror and makes yum download from it, not some random one. Usually, this plugin works very well, but this time it didn't. I tried to reset everything with

yum clean all

and than again

yum update

But it didn't help. Googling around I quickly determined that the first command didn't remove fastestmirror's data. What is necessary is to remove cache file stored in /var/cache/yum/x86_64/17/timedhosts.txt (this is location on 64-bit Fedora 17). Well, guess what, this didn't help either. Namely, fastestmirror plugin determines which mirror is the best one based on measuring how much time is necessary to establish connection with a mirror, and then it immediately disconnects. This is all OK, until mirror starts to apply some throttling effectively capping maximum speed. And this was exactly what happened to me.

It used to be possible to send SIGINT signal to yum (pressing Ctrl+C) on which yum would switch to another mirror. But this doesn't work any more. When you press Ctrl+C yum exits. Now, this is expected behavior, but the previous one was actually useful! So, there should be some way to tell yum to switch to next mirror.

In the end I solved this by looking which mirror(s) yum was using. This is printed when yum starts, e.g.:

Loading mirror speeds from cached hostfile
 * fedora: gd.tuwien.ac.at
 * fedora-debuginfo: fedora.inode.at
 * rpmfusion-free: mirrors.coreix.net
 * rpmfusion-free-debuginfo: mirrors.coreix.net
 * rpmfusion-free-updates: mirrors.coreix.net
 * rpmfusion-free-updates-debuginfo: mirrors.coreix.net
 * rpmfusion-nonfree: mirrors.coreix.net
 * rpmfusion-nonfree-debuginfo: mirrors.coreix.net
 * rpmfusion-nonfree-updates: mirrors.coreix.net
 * rpmfusion-nonfree-updates-debuginfo: mirrors.coreix.net
 * rpmfusion-nonfree-updates-testing: mirrors.coreix.net
 * rpmfusion-nonfree-updates-testing-debuginfo: rpmfusion.blizoo.mk
 * updates: gd.tuwien.ac.at
 * updates-debuginfo: fedora.intergenia.de

The problem was Fedora's main repository, which was downloaded from gd.tuwien.ac.at. So, I edited fastestmirror's configuration file /etc/yum/pluginconf.d/fastestmirror.conf and added the following line:

exclude=.at

That excluded a bit more mirrors than I intended, but it definitely solved my problem.

List all tabs across all windows in Firefox...

I have a lot of windows opened at the same time, and in each window there are many tabs. This makes it a nightmare to find a specific tab; you have to go window by window, and tab by tab. So, I just spent half an hour, maybe more, searching for a way to list all tabs that are opened in all windows. It turns out that there is not much information. In majority of cases you'll find news and tips on how to see all tabs in a single window (that one is easy) but not much than that. I also found a post how to do it in Safari, but not in Firefox. Finally, I came across this post in which poster is looking for a way to search all tabs in all windows. One of the responders mentioned a plugin called Tabhunter, which did the trick. So, to make this particular problem more visible in Google searches, I'm writing this post.