Many different programs are available, and they all provide a different set of features, options, and output formats. When choosing, consider the degree of control you want to have over your video resolution and whether the video is intended to work on non-Linux operating systems. Common open source output formats, such as FLAC and Ogg Theora, work natively on Linux but require software and plugins on proprietary operating systems. User interfaces also vary greatly; some applications are nothing more than an icon in the system tray while others depend on large interfaces with many options.

I tested three popular screencasting applications to see which is best for everyday use. I evaluated the user interface, the quality and variety of output formats, and the ease of installation and obtaining the required dependencies. I tested the programs on a MacBook Intel Core 2 Duo with 4GB of RAM, dual-booting into Ubuntu 8.04 Hardy Heron.

Istanbul

Istanbul is a simple desktop recorder that lives in your system tray. Clicking on the icon starts the recording session, and clicking it again ends it. The video is encoded in the Ogg Theora format. You can capture the full screen, a selected window, or a portion of the desktop, with or without sound.

This application doesn’t have a complicated user interface, making it easy to use, but there are some drawbacks. Although you do have some control over the resolution size, you cannot change the output format of the video file. This isn’t much of a problem if you’re going to upload the video to a Flash-based video site, but the Ogg Theora format doesn’t work out of the box of the main proprietary operating systems without an application like the VLC media player. Therefore, you’ll have to convert to a different format if your intended audience requires it.

Istanbul is easy to install, and it is included in most distribution repositories. In Ubuntu, I was able to install it with the Synaptic Package Manager. It requires PyGTK and GStreamer, which are common dependencies.

Wink

Wink is geared toward making video tutorials; it compiles a series of screenshots to a Flash format, and allows you to edit the video directly and add text boxes, navigation buttons, and still images. It includes many advanced features, such as the ability to create preloaders (elements that load portions of the video before it starts playing) and control bars for the Flash playback.

The interface is not as minimal as Istanbul’s, but it is still relatively straightforward. The main drawback of Wink is the video output formats: Flash and Windows .exe programs are good for viewing the video when the file is local or when it is hosted on a personal Web site, but you can’t upload Flash and .exe files to most social networking and video sharing sites. Wink is good for corporate entities who want to share a tutorial with staff, but it is less useful for home users who want to show off their desktop on YouTube.

Most distributions include Wink in their repositories, and you can install it with any package management application. Unfortunately, though, Wink doesn’t work with Ubuntu 8.04 as of the writing of this article without some hacking. I tested it for this review with a previous version of Ubuntu.

XVidCap

With XVidCap, you can capture desktop video and take single-frame screenshots. You can record portions of the screen by dragging a red selection rectangle over the area you wish to capture. The program can handle a wide variety of output formats, including MPEG, AVI, Flash, and QuickTime.

The interface consists of a small toolbar with more options tucked away inside a Preferences panel. XVidCap uses the FFmpeg libraries to capture video or a series of images, and it can also embed audio. Some people claim that XVidCap can dramatically slow down your computer if you try to record a large area. I didn’t have that problem on my machine, but I had 4GB of RAM.

Installation of XVidCap is easy because it comes in the repositories for most distributions. It requires common dependencies, such as libavcodec (the FFmpeg codec libraries for video), and Cairo, Glade Interface Designer, and GTK+ to render the graphical interface.

Conclusion

XVidCap is the most versatile of these three tools for recording your desktop and creating screencasts. Istanbul is a close second, but its lack of support for a variety of different output types is a drawback. Wink is nice, but it’s limited in use to only a few tasks, and it’s not for users who merely want to record their desktops. XVidCap can handle many popular video formats, allowing it to play nice with both Windows and Mac OS X. The red selection box is kind of clunky, and there is no easy way to record only a specific window without it, but XVidCap gets the job done in an efficient manner.

TimeVault makes saving and recovering data easy through an automatic process. You define directories to include or exclude from the process, and TimeVault takes care of the rest by creating snapshots of your data. A snapshot is a clone of a directory at a point in time. Files are copied if they’ve changed since the last snapshot. If a file hasn’t changed, it is simply referenced to an older snapshot and no space is used for backing it up. Snapshots are read-only, so they are protected from accidental deletion or modification. If you are the root user, you can delete intermediate snapshots without harming the rest of them. Because of that, you can still restore to a point before or after the deleted snapshot. When you pick what files to exclude, you can specify either a path or a pattern to identify files, which is especially handy if you want to exclude large media files or music directories.

TimeVault can make backups even easier by automating them. It can be set to take a daily snapshot of included directories without you having to do anything, and will let you know when the automatic snapshot is finished with a notification in the system tray. Automatic snapshots are optional, and can be enabled in the preferences dialog by checking the “Enable automated snapshots” option on the General tab.

Snapshots expire when certain conditions are met, such as after a defined number of days, when enough snapshots have been taken for a single file, or when too much space is used for a file. You can edit and adjust these settings in the Expire tab of the preferences dialog.

It’s simple to restore data with the Snapshot browser. It displays a timeline of all the snapshots taken, the data included, and the size and the number of files in any given snapshot. You can also search the snapshots to find one with a specific file, which is useful if you want to restore a deleted document. You can also delete backups from the Snapshot browser without having to go through the filesystem manually. Also, TimeVault can revert all of the monitored directories back to a certain snapshot. You just select the snapshot and click the Revert button in the bottom right corner.

TimeVault’s restoration features are integrated into Nautilus, the GNOME filesystem browser. By right-clicking on a file and selecting the Properties option in the context menu, and selecting the Previous Versions tab (indicated by the TimeVault icon), you can see how many previous versions of the file are stored in snapshots, as well as other basic information. At the bottom of the dialog there are buttons to launch the Snapshot Browser to restore previous versions of files.

Installing TimeVault

TimeVault is not yet part of the Ubuntu repositories. Because of that, you have to download and install a .deb package from the Launchpad project site.

After the .deb package is installed, you can start TimeVault Notifier manually from Applications -> System Tools -> TimeVault in the GNOME menu panel. The Notifier consists of the system tray icon and notifications for completed snapshots, and has convenient access to preferences and the Snapshot Browser. The TimeVault back end will run all the time. For most people, it is easier if the TimeVault Notifier begins at startup. To do this, open the Session configuration panel from System -> Preferences -> Sessions in the GNOME panel. Click on the Add button, type “TimeVault Notifier” in the name box, and “/usr/bin/timevault-notifier” in the path box. Click OK when finished. Next, you should specify a directory to store TimeVault snapshots with a command like sudo mkdir /home/timevault/ . If you skip this, the snapshots will go into the root directory, and that can make things messy.

Tell TimeVault to use that directory by selecting it in the Snapshots Root Directory option under the General tab of the preferences dialog. Lastly, be sure to visit the Include and the Exclude tabs of the preferences dialog to tell TimeVault which files to put in the snapshot. As soon as you finish that, the application will make its first backup.

You can customize an Ubuntu 8.04 Hardy Heron live CD to make a good bootable utilities disk by adding and removing packages from the standard installation. Specifically, you can remove most of the Ubuntu applications and install antivirus, a partition recover tool, a few disk utilities, and a rootkit checker, among other things. I’m going to create the live CD within an Ubuntu installation, but the directions should work for most Debian-based operating systems, and can be easily ported elsewhere. This guide largely follows the community documentation article on the Ubuntu customization process, which is a good place to look for more advanced information and troubleshooting support, while the livecdlist.com wiki is the best place to look for customized directions.

To create and use the Ubuntu-based boot CD, you’ll need a computer with at least 3GB of disk space and 512MB RAM. 1GB of swap is recommended, though I did it with 512 MB.

Create the live CD environment

The first step is to download the Ubuntu 8.04 live CD ISO file for your system type. You can get it from the Web site, or you can use wget on the command line:

wget -v http://releases.ubuntu.com/hardy/ubuntu-8.04-desktop-i386.iso

To work with the image, you’ll need to install a few packages to support the squashfs filesystem format, and mkisofs, the utility to create ISO images. On Ubuntu, you can install them with the command sudo apt-get install squashfs-tools mkisofs.

Now, load the squashfs module, then copy, mount, and extract the contents of the ISO file in order to customize the contents:

sudo modprobe squashfs
mkdir rescue
mv ubuntu-8.04-desktop-i386.iso rescue
cd rescue
mkdir mnt
sudo mount -o loop ubuntu-8.04-desktop-i386.iso mnt
mkdir extract-cd
rsync --exclude=/casper/filesystem.squashfs -a mnt/ extract-cd
mkdir squashfs
sudo mount -t squashfs -o loop mnt/casper/filesystem.squashfs squashfs
mkdir edit
sudo cp -a squashfs/* edit/

You’ll want to customize the CD in a chroot environment. Chroot changes the root directory of the environment, allowing you to access the files and applications inside the CD directly, which you must do in order to use tools like apt-get. In order to use a network connection inside chroot, which you’ll probably want to do to add new packages, you’ll need to copy in the hosts and resolv.conf files to configure your network settings. You can achieve this with the following:

sudo cp /etc/resolv.conf edit/etc/
sudo cp /etc/hosts edit/etc/

Once you’ve completed these steps, you can start to work inside the live CD. Mount the live CD to the edit/dev mountpoint, then change your root directory into the newly mounted volume. You’ll need to mount /proc and /sys volumes to work with the kernel, and export your settings to avoid locale and GPG problems later on:

sudo mount --bind /dev/ edit/dev
sudo chroot edit
mount -t proc none /proc
mount -t sysfs none /sys

export HOME=/root
export LC_ALL=C

Free space by removing unneeded packages

You can configure the packages that are included with the live CD using apt-get or Aptitude. You’ll want to free up some space to add the rescue applications; even though the data is compressed, all of it needs to fit on a 700MB CD or on a higher-capacity DVD. You can remove packages and applications that aren’t useful for the recovery. I chose to remove the OpenOffice.org suite, the GNOME games set, Ekiga, Ubiquity, Evolution, and the GIMP, saving me around 200MB. If you are comfortable without a command-line environment, you might want to get rid of GNOME and Xorg; if you do that, you need not install GParted and the other graphical tools in the next section. In any case, the goal is to get rid of large applications. To sort all of the installed packages by size, run the following command in the chrooted environment:

dpkg-query -W --showformat='${Installed-Size} ${Package}\n' | sort -nr | less

You can use apt-get to remove a package. Use it with the --purge argument to get rid of configuration files. The sudo command won’t work in the chroot, and therefore should be omitted:

apt-get remove --purge package-name

Add rescue applications

Once you have removed all of the unneeded applications from the live CD you can start to add rescue and recovery applications. Generally, rescue CDs include a variety of disk utilities and security tools, as well as networking tools to find support and access outside machines. You may not want all of the applications I mention, and you can add some that I don’t. This is your personal boot CD, and should be configured as you see fit. For ideas about what to include on your CD, you might want to check out some of the prebuilt rescue distributions mentioned in the sidebar.

You can install packages from the repositories using apt-get, but you must add the multiverse repository to your /etc/apt/sources.list file:

deb http://us.archive.ubuntu.com/ubuntu/ hardy main multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ hardy main multiverse

A disk partition tool is the staple of a mature boot disk. Fortunately, the Ubuntu live CD comes with GParted, the GNOME Partition Editor, so adding a package isn’t required. If you chose to forgo a graphical environment, you should make sure that parted is installed instead to handle partition tables from the command line. If you accidentally delete a partition, installing a program like testdisk can help you recover it, as well as provide a few other basic disk tools. If you are using the ext2 filesystem type and you accidentally delete a file, you’ll find the e2undel package helpful in recovering it. If you need to copy an entire partition from a dying disk, or just want to make a backup, partimage is the way to go. You can also use it to restore a partition with a previously made backup.

If you plan to use this disc with Windows machines, you will want to install antivirus and rootkit tools. Clamscan provides quick and easy virus scan with a command-line-based update tool. Chkrootkit is a scanner to find and remove rootkits that could be hiding in your computer. You can use sleuthkit to conduct analysis of your filesystem and browse through hidden files.

After you finish adding packages, clean up your temporary data and unmount the environment:

apt-get clean
rm -rf /tmp/*
rm /etc/resolv.conf
umount /proc
umount /sys
exit
sudo umount edit/dev

Now, regenerate the manifest (which is basically a list of installed packages) and copy in into the correct directory:

chmod +w extract-cd/casper/filesystem.manifest
sudo chroot edit dpkg-query -W --showformat='${Package} ${Version}\n' > extract-cd/casper/filesystem.manifest
sudo cp extract-cd/casper/filesystem.manifest extract-cd/casper/filesystem.manifest-desktop
sudo sed -i '/ubiquity/d' extract-cd/casper/filesystem.manifest-desktop

Compress the filesystem to squeeze it onto a disc:

sudo rm extract-cd/casper/filesystem.squashfs
sudo mksquashfs edit extract-cd/casper/filesystem.squashfs -nolzma

And finally, create the ISO file:

cd extract-cd
sudo mkisofs -r -V "$IMAGE_NAME" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o ../ubuntu-8.04-desktop-i386.iso

Once the image file is created, you need to burn it to a disc. You can do that pretty easily with K3b or Brasero. If you want, you can do it from the command line:

cdrecord dev=/dev/cdrom ubuntu-8.04-desktop-i386.iso

Once the CD is finished burning, you should be able to put it into your optical drive and boot into the environment you just created.

This should give you more than enough information to start building your ultimate custom rescue CD. Add the packages and tools you need, and hopefully you’ll never be at a loss the next time your computer has a problem during startup.