BREAK

Sets or clears extended CTRL+C checking. You can also use this 
command at the command prompt or in your CONFIG.SYS file.

You can press CTRL+C to stop a program or an activity (file 
sorting, for example). Typically, MS-DOS checks for CTRL+C only 
while it reads from the keyboard or writes to the screen or a 
printer. If you set BREAK to ON, you extend CTRL+C checking to 
other functions, such as disk read and write operations.

For more information, please refer to MS-DOS Help or Windows NT 
command line command help.