Tuesday, July 10, 2007

Screencasting in Linux

Screencasting, according to wikipedia, stand for record computer screen output, often containing a narration. Then, screencasting can be used for many different and useful purposes. In particular, people working with computer systems can share their expertise with anothers posting video-howtos about, almost, any thing to deal with computers.

Now, many open source and free applications are available in order to do screencasting for the Linux platform.

Today, i want to mention two complementary tools to support the screencasting process in Linux. The first is xvidcap. It can be found in the ATrpms repository. You only need execute the command, yum install xvidcap. It allows you define a rectangular section of your screen, then you can record all the things to happen there.

When you end to recording, probably you need editing the video generated. Then, I recommend to use Kino. Kino, is a basic tool for edit videos and as easy to install as execute yum install Kino. If you are familiar with vi editor you will find many key sequence use for edit text in vi, works for edit video in Kino, for example: "x" key allows you delete a character in vi, similarly, when you are editing a video with Kino, "x" key allows you to delete a frame. Very funny and wonderful for us, the vi users. :-D.

  • ATrpms
  • Screencast
  • Tools A complete article to describe different tools for screencast in Linux.
  • ScreenKast is a new project under screencast category. Automatically, it allows upload videos and publish them on internet.
  • Istanbul is an advanced video editing tool, however, demands a lot of hardware requirements.

Saturday, July 7, 2007

I'm user of Fedora Core Linux distribution, release 6, although at this moment release 7 is available.

Fedora as every major Linux distribution due to licensing issues cannot distribute in its official repositories (Fedora Base and Fedora Extra) software to playback MP3 or DVD files. However, there exist alternative repositories such as:
Some packages are incompatible between them, e.g. you can get compatibility problems if install livna and freshrpms at same time.

Recently, i'm interested in work with to do video tutorials for grid tasks and found that freshrpms repository fulfit my needs.

Useful Links

Tuesday, July 3, 2007

How to clone a XEN VM


today, I will describe what is the manual process to clone a virtual machine (VM) using XEN technology. (Fedora Core 6 (FC6) is the distribution installed in the server.)

Ok, assume I want to clone the VM "os_template". The information related to this VM reside in the file "os_template" located in the "/var/lib/xen/images" directory. Be sure, the VM "os_template" is shut off. Then, make a copy of the os_template file:

dd if=/var/lib/xen/images/os_template of=/var/lib/xen/images/os_copy bs=4k

Now, extract the VM configuration:

virsh dumpxml os_template > os_template.xml

this is the os_template.xml's content:

<domain type='xen'>
<disk type='file' device='disk'>
<driver name='file'/>
<source file='/var/lib/xen/images/os_template.disk'/>
<target dev='xvda'/>
<interface type='bridge'>
<mac address='00:16:3e:65:82:48'/>

now, modify next fields: name, uuid, source (file attribute), mac (address attribute). Save the modifications. I'll assume that the name given to your VM will be os_copy. Then, execute this commands:

virsh define os_template.xml
virsh start os_copy

The job is done!

Some relevant urls: