Ubuntu uses Upstart, as does Fedora 9 and later. There is no direct equivalent to /etc/inittab, as startup scripts run asynchronously. Each script in /etc/event.d serves a similar purpose to a line on a traditional inittab.
The /etc/inittab file is a script that controls most of the boot sequence. It dictates what programs and scripts to launch and at what runlevels.
man 5 inittab
using i cloud
The inittab file contains descriptions of the run states that your system is allowed to assume. Configure it to contain the default runlevels your system will assume when it boots.
WAV is a file format. There is no difference between a WAV file on Ubuntu and a WAV file on Windows.
Ubuntu uses many file formats, many of which are shared with Windows and Macintosh. The partition format the Ubuntu generally uses is an ext4 filesystem.
Ubuntu uses the ext4 file journaling system, which doesn't get fragmented.
Since Ubuntu is installed as an ext4 file system (not NTFS as in Windows), there is no need to defragment anything.
The default file manager in Ubuntu (Unity and GNOME) is Nautilus. In Kubuntu and KDE, it is Dolphin. You can install other file managers, such as Konqueror, and Thunar.
By default it should be using the ext3 file system, but you have a choice of several, including ext2, reiserfs, etc. Newer versions of Ubuntu tend to install as ext4 file systems, however if you've upgraded from an older version then you'll keep your original file system.
The program is saved in the Home directory, usually in the Downloads file.
There are several: .sh .bin .deb .rpm .py...