This mode employs a different disk file from that used for timed input. In sequential mode, the keywords and functions appear as a sequence of card images, and these lines are processed sequentially, as rapidly as they can be executed. When data-taking program activations are encountered, the system goes into a "wait state" until the routine has finished, then line processing continues. The CARD keyword itself may also be used in the command file as a way of setting up an infinite loop of commands.
To enter this untimed input mode, the user enters the CARD command. If the CARD command is given with no arguments, then processing starts with the first line image in the file. If an integer n is given as an argument, then processing begins with the nth card image in the file. Upon entry into this mode, the flag "CARD" will appear at the top of screen 1.