"The distribution usually ships as a Live DVD which can
optionally be installed if needed for use as a regular operating
system. There are few different boot options available including
Default text mode, Stealth mode and Forensics mode. The Stealth
mode boots the OS with networking disabled and the Forensics mode
boots without automatically mounting drives or swap space. The
default mode boots into the customized Unix/Linux shell from which
you can run the desktop environment.
BackTrack 5 comes with more than 300 security tools that are all
open-source and freeware.