The organization is a dentist office. When new patients are seen for the first time, they complete a patient information form that asks for their name, address, phone number, and brief medical history, which are stored in the patient information file. When a patient calls to schedule a new appointment or change an existing appointment, the receptionist checks the appointment file for an available time. Once a good time is found for the patient, the appointment is scheduled. If the patient is a new patient, an incomplete entry is made in the patient file; the full information will be collected when the patient arrives for the appointment. Because appointments are often made far in advance, the receptionist usually mails a reminder postcard to each patient 2 weeks before the appointment.

Step 1. Draw a physical level 0 data flow diagram (DFD) for the following dentist office system.