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State Diagram for a DVD Player — Key States
publish date: 2026/06/08 22:17:21.507130 UTC
volume_mute
You are asked to draw a state diagram for the control software of a DVD player. Which of the following are valid states for such a system? Select all that apply.
Correct Answer
(1) Standby (no disc inserted, player waiting)
(2) Loading (disc being read and recognized)
(3) Playing (disc playing, display shows elapsed time)
(4) Paused (playback frozen, display shows pause indicator)
(5) Menu (on-screen menu being navigated)
Explanation
Valid states for a DVD player model are modes the system is in, each with associated actions. Standby, Loading, Playing, Paused, and Menu are all valid system states with distinct behaviors. 'The user's hand pressing the play button' is a stimulus (event) that triggers a state transition — not a state itself. In a state diagram, stimuli are the labeled arrows, not the rounded rectangles.
Reference
Software Engineering, Ian Sommerville, 9th edition