A Level Computer Science OCR Practice Exam

The capacity of optical storage, such as CDs, DVDs, and Blu-rays, primarily depends on patterns etched on the disc surface. These patterns are typically in the form of pits and lands that represent the binary data stored on the disc. The density of these patterns determines how much data can be packed into a given area on the disc's surface, contributing directly to its overall storage capacity.

For instances like DVDs and Blu-ray discs, advances in technology have allowed smaller and more densely packed pits and lands compared to traditional CDs. This miniaturization increases the capacity while maintaining physical disc size. The structure and design of these patterns, along with the wavelength of the laser used in the reading process, are critical factors that impact the amount of data that can be stored and retrieved.

In contrast, factors mentioned in other options, like the type of magnetic material or configurations of memory chips, pertain to different types of storage media, such as magnetic storage (hard drives) or solid-state drives (SSDs), and are not relevant to optical storage technology.