CDD.SYS
CDD.SYS is the driver for the CDD tool. CDD.SYS shells OS/2's standard CMD. CDD is a tool to shell to OS/2 before the Presentation Manager (and WorkPlace Shell) is started. When CDD is installed, you can press <Esc> at the message "Press ESC for command prompt..." to invoke the shell. If you do not press <Esc> OS/2 continues to boot.
DEVICE=<path>CDD.SYS