Archive for July, 2007

Fedora 7 Desktop effect causes Multimeda playback problems

Recently, I enabled the desktop effect on my Fedora 7. Shortly afterwards, none of the videos can be played back. Whenever I play a video file, it would load the file and then suddenly quit the application. This happened with any sort of video player.

If you run the video¬†from the command line, you’ll see the following message:

X Error of failed request: BadAlloc (insufficient resources for operation)
Major opcode of failed request: 140 (Xvideo)
Minor opcode of failed request: 19 ()
Serial number of failed request: 84
Current serial number in output stream: 85

The message is from running VLC. However, running gxine and totem also result in essentially the same bad alloc message.

There is some sort of incompatibility between the Desktop effect and multimedia playback. This problem does not occur if you run as the root account. Whenever you run as a non-root, multimedia playback would failed as long as Desktop effect is on. You either have to turn off Desktop effect or run as root.


July 6, 2007 at 10:35 pm 6 comments

Installing VirtualBox on Fedora 7 with a Windows Guest

Fedora 7 comes with Xen. However, I got rid of it because I had great difficulty getting it to work with the wireless drivers. One of the selling point with Xen is that it uses Paravirtualization. Paravirtualization is suppose to have higher performance than vmware. However, unless you have a processor that have hardware assisted virtualization (Intel VT-x or AMD-V), you need to run a modified version of the OS. Since windows can’t be modified and since my laptop has a Celeron M with no VT-x support, I cannot run windows under Xen.

I was going to install Vmware, the old standby, but various people mentioned VirtualBox. Supposedly, performance is a bit faster than VMware, so I decided to give it a try.

Versions of VirtualBox

There are actually 2 versions of Virtual Box.

  • Standard version – Not open source but free for use for personal and educational purpose.
  • OSE version – Open source version with some features missing and no installer.

Unless you are hardcore open source advocate, you should download the standard version. The OSE version doesn’t even have an installer. To download VirtualBox. See

Installing VirtualBox

You can download VirtualBox from the download page There is actually a link for a Fedora 7. When you download the software, you’ll notice that the file is .run. What in the world is that? It is a shell script. Type in the following command to convert it back to a RPM.

sh ./

Now, you can install it using Yum.

yum -Uvh

Allowing your user to use VirtualBox

The installer installs a group “vboxusers”. Any user who wish to use VirtualBox must be in this group. You can easily do this by selecting the menu item System->Administration->User and Groups.

Creating a Windows Guest

Now that we have a drive device, we can create a Windows Guest.

  1. Launch VirtualBox by selecting  F->System Tools->innoTek VirtualBox.
  2. Click on the New button and follow the wizard. In my case, I specified a Windows 2000 setup with a RAM size of 256 Mb, and a virtual disk of 4 Gb.
  3. Next, we configure the new virtual machine by selecting it and clicking on Settings. You can play around with each settings. At the very least, enable the CD-ROM so you can install the Windows OS.
  4. Now, we have to install the Windows OS. Insert the disc into the CDROM and double-clicking on the machine. It will launch and boot from the CD-ROM. Follow the instruction and install the windows OS.

Installing the Windows Guest Addon for a better display

When you launch windows, you’ll notice that you are limited to 640×480 and only 16 colors. In fact, a lot of software will bomb on it because of the video settings. To get a better video,you need to run the guest add-on.

  1. Boot into your virtual machine.
  2. In your virtual machine window, select Devices->Install Guest Additions. This will mount the special Guest ISO and launch the setup program.
  3. Follow the wizard and install the addon.

After the addon is install, you’ll notice that you have a much better options for video size and depth.

Jumping in and out of the virtual machine

If you move your mouse to inside the virtual machine, it will be capture and then your mouse will remain inside the virtual machine window. To get out, press the right ctrl key. Note that this key can be change.


I haven’t ran any benchmark, but the virtual machine runs reasonably fast, even with only 256 Mb of memory and in virtual disk mode. I am generally happy with the product. It is much easier to config than Xen and its interface is as nice as VMware.

July 5, 2007 at 8:43 pm 8 comments

What is the difference between localhost and localhost.localdomain on MySQL

This is one of the things that confused me for a long time because it isn’t mentioned in a lot of MySQL documentation. In MySQL in Linux, you can do the following:

mysql -u root -p
select user, host from mysql.user;

You may get the following output returned:

| user | host                  |
|      | localhost             |
| root | localhost             |
|      | localhost.localdomain |
| root | localhost.localdomain |
4 rows in set (0.00 sec)

What is the differences between localhost and localhost.localdomain? Both localhost and localhost.localdomain refers to the local computer. The difference is as followed:

  • The host localhost allows connection to mysql through the UNIX socket.
  • The host localhost.localdomain allows connection to mysql through TCP/IP.

When you type mysql and don’t specify a host, it will connect via UNIX socket. If you type mysql -h localhost.localdomain, it will connect via TCP/IP. You can check which which connection you are at when you type the command status. The line connection will list either UNIX socket or TCP/IP.

Connecting through the UNIX socket has a lower overhead than through TCP/IP, but not every client can connect to a UNIX socket.

July 4, 2007 at 12:10 am 1 comment


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