The ATM machine is a computing device. A more detailed analysis, identifying each of its actions as computing capabilities, follows.

Input:

• User inserts ATM card.
• Card contains magnetic strip.
• Strip contains encoded information (name, bank ID, acct. ID)
• This info is input into the machine, which allows it to identify you.
• User types PIN on keyboard.
• PIN is used to verify that you are the legitimate owner of the card.
• PIN is compared with information stored on your bank's computer.
• User uses keypad to specify what (s)he wants to do.

Output:

• The screen prompts the user with a menu of choices and other instructions.

More Input:

• The user presses keys as appropriate.

Storage/Retrieval:

• Your bank's computer has your account info stored in a special place under your account ID (e.g., current account balance).
• If the user presses the key for "Show Account Balance", this information is retrieved and output on the display panel.