The document discusses various common disaster recovery tools used in Unix and Linux systems. It describes tools such as mksysb and NIM for AIX, make_tape_recovery and make_net_recovery for HP-UX, and Mondo Rescue and Clonezilla for Linux. It provides an overview of these tools' capabilities and limitations, how they can be used to back up systems to tape drives or over the network, and examples of commands to perform backups and restores.