The first video explains why a computer needs secondary storage, and explains what is meant by primary and tertiary storage.
The second video explains what is meant by the term “capacity” of storage devices. The relative size of different types of files is introduced. (More detailed explanations of this can be found in the 2.6 Data representation topic.) Data capacity requirements for a range of typical storage scenarios are explained in a similar way to how questions of this nature would be presented in exams.
In the third video various types of secondary storage devices are introduced including optical, magnetic and solid state. Typical uses of these devices are discussed, explaining the reasons why they are a good choice for different situations. This provides students with a broad knowledge of this topic that can be applied to new scenarios in exams.
The fourth video explores secondary storage devices in more detail by comparing and contrasting their features. This includes capacity, speed, portability, durability, reliability and cost.