Difficulty: Easy
Correct Answer: Can hold more data
Explanation:
Introduction / Context:
DVD technology encodes tiny pits and lands in a spiral track read by a laser. Dual-layer discs add a second, semi-reflective information layer. Understanding what benefit this provides helps in selecting media for archiving and playback.
Given Data / Assumptions:
Concept / Approach:
A dual-layer DVD increases capacity by storing data across two layers along the optical axis. The drive refocuses the laser to read the second layer. Typical capacities: single-layer around 4.7 GB, dual-layer around 8.5 GB. Speed largely depends on the drive’s rotation and data rate, not merely the number of layers.
Step-by-Step Solution:
Compare single-layer and dual-layer structures.Recognize that an extra information layer means additional usable surface area for pits/lands.Conclude: the practical benefit is higher storage capacity, not an inherent speed boost or automatic backup.
Verification / Alternative check:
Media specifications from manufacturers list “DVD+R DL” or “DVD-R DL” capacities near 8.5 GB, approximately doubling single-layer capacity.
Why Other Options Are Wrong:
Common Pitfalls:
Assuming dual-layer equals better performance. It mainly raises capacity; compatibility or seek latency might even be more complex due to layer switching.
Final Answer:
Can hold more data
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