This module discusses DOS commands for preparing bootable devices. It explains that DOS commands are used to communicate with MS-DOS and other command line applications. The module then covers how to use the DISKPART command to prepare a USB drive to be bootable. Steps include cleaning the drive, creating a partition, formatting it, and making it active. It also discusses using the bootsect command to create a boot sector and copying installation files to complete the process. The key points are that DOS commands provide an interface for older systems and preparing bootable devices allows using removable media to install an operating system.