Packet writing treats the CD or DVD disk like a hard drive in which you create a file system (like ext3) and format the disk, and then write to it randomly as you would to a conventional hard drive. This method, although commonly available on Windows-based computers, is still experimental for Linux and is not yet covered in detail here.
DVD+RW media are capable of only about 1,000 writes, so it is very useful to mount them with the noatime option to eliminate any writing to update their inodes or simply mount them read-only when it's not necessary to write to them.
It is possible to pipe data to the growisofs command:
# your_application | growisofs -Z /dev/scd0=/dev/fd/0
It is also possible to burn from an existing image (or file, named pipe, or device):
# growisofs -Z /dev/scd0=
The dvd+rw-tools documentation, found at /usr/share/doc/dvd+rw-tools-*/index. html, is required reading before your first use of the program. We also suggest that you experiment with DVD-RW (rewritable) media first, as if you make mistakes then you will still be able to reuse the disk, rather than creating several new coasters for your coffee mug.
Sound and Music
Linux historically had a reputation of lacking good support for sound and multimedia applications in general. However, great strides have been made in recent years to correct this, and support is now a lot better than it used to be. (It might make you smile to know that Microsoft no longer supports the Microsoft Sound Card, but Linux users still enjoy support for it, no doubt just to annoy the folks in Redmond.) Unix, however, has always had good multimedia support as David Taylor, Unix author and guru, points out:
'The original graphics work for computers was done by Evans & Sutherland on Unix systems. The innovations at MIT's Media Lab were done on Unix workstations. In 1985, we at HP Labs were creating sophisticated multimedia immersive work environments on Unix workstations, so maybe Unix is more multimedia than suggested. Limitations in Linux support doesn't mean Unix had the same limitations. I think it was more a matter of logistics, with hundreds of sound cards and thousands of different possible PC configurations.'
That last sentence sums it up quite well. Unix had a limited range of hardware to support; Linux has hundreds of sound cards. Sound card device driver support has been long lacking from manufacturers, and there is still no single standard for the sound subsystem in Linux.
In this section, you learn about sound cards, sound file formats, and the sound applications provided with Fedora.
Sound Cards
Fedora supports a wide variety of sound hardware and software. Two models of sound card drivers compete for prominence in today's market:
> ALSA, the Advanced Linux Sound Architecture, which is entirely open source
> OSS, the Open Sound System, which offers free and commercial drivers
Fedora uses ALSA because ALSA is the sound architecture for the 2.6 series kernels.
ALSA supports a long list of sound cards. You can review the list at http://www.alsa-project.org/alsa-doc/. If your sound card is not supported, it might be supported in the commercial version of OSS. You can download a trial version of commercial software and test your sound card at http://www.opensound.com/download.cgi.
Fedora detects most sound cards during the original installation. If you add or replace a sound card after the initial install, the Kudzu New Hardware Configuration utility automatically detects and configures it at the next reboot. To configure the sound card at any other time, use the system-config-soundcard graphical tool. The graphical tool can be found under the System, Administration menu as the Soundcard Detection menu item.
Adjusting Volume
Fedora now benefits from the inclusion of PulseAudio, a new way of controlling sound across Fedora. Instead of having a single global volume level, PulseAudio allows you to tailor each program to your specific needs. You may want to have music played at a louder volume than video; this is easy to do with PulseAudio, which is found under Applications, Sound and Video, as seen in Figure 7.14.
FIGURE 7.14 Control the volume level for each application that is currently handling sound with the volume slider.
You can also set the global output volume by using the slider found under the Output tab.
Alternatively you can control all the output volumes for the system to make sure that you have set everything to your taste, as shown in Figure 7.15. To access the volume control, right-click on the speaker icon and select Open Volume Control.
FIGURE 7.15 Use the volume control to manage volume settings for all your sound output devices.
Sound Formats
A number of formats exist for storing sound recordings. Some of these formats are associated with specific technologies, and others are used strictly for proprietary reasons. Fedora supports several of the most popular sound formats, including
> raw (.raw) — More properly known as
> MP3 (.mp3) — A popular, but commercially licensed, format for the digital encoding used by many Linux and Windows applications. MP3 is not supported by any soft ware included with Fedora (which advises you to use the open source Ogg-Vorbis format instead).
> WAV (.wav) — The popular uncompressed Windows audio-visual sound format. It is often used as an intermediate file format when encoding audio.
> Ogg-Vorbis (.ogg) — Fedora's preferred audio encoding format. You enjoy better compression and audio playback, and freedom from
