The program will tell the CPU how to process the input information and what form to send the output in. For example, we might use a keyboard to send some text input into the computer .

In the example below, the program asks the user to enter their name, which is stored in the variable called ‘name’: OUTPUT “Please enter your name: “ name ← INPUT ...

Then, you can see the program output on the display screen. If the program output gets sent to your printer’s FD, the output would be printed. 0, 1, and 2 are used as file descriptors for stdin, ...