SS 2 First Term

Lesson objectives

By the end of the week, learners should be able to:

1. Define secondary storage and distinguish it from main memory.
2. Name four magnetic, optical and solid-state technologies.
3. Convert between bytes, kilobytes, megabytes, gigabytes and terabytes.
4. Compare storage technologies on capacity, speed, portability and cost.
5. Describe backup strategy using external drives and cloud copies.

Key vocabulary

• Secondary storage: long-term holding of files when the power is off.
• Capacity: the amount of data a device holds.
• Speed: how quickly data can be accessed.
• Portability: how easily a device moves between locations.
• Cost: the purchase and maintenance price.
• Magnetic storage: stores data magnetically, such as a hard drive.
• Optical storage: read by a laser, such as a CD or DVD.
• Solid-state storage: flash memory with no moving parts.
• Backup: a redundant copy stored separately.

Common misconceptions

• "Secondary storage is always faster than RAM." SSDs and HDDs sit outside the CPU bus.
• "More storage is always better." Too much storage wastes money and management effort.
• "Cloud is a replacement for backups." Cloud provides redundancy but still needs local copies too.

Teacher activities

1. Starter: ask where a saved file sits when you turn off the lab computer.
2. Define secondary storage and contrast it with main memory.
3. Build the unit ladder bit byte KB MB GB TB and work two conversions.
4. Pass around an HDD, a CD, a flash drive and a memory card.
5. Compare capacities by converting and asking how many CDs equal one DVD.
6. Introduce backups as separate copies stored elsewhere.

Student activities

1. Answer the starter and identify where saved files sit.
2. Define secondary storage in their own words and contrast with main memory.
3. Complete five unit conversions showing the working.
4. Identify each device passed round and write its storage technology.
5. Solve two capacity conversion problems with the method shown.
6. Describe a backup strategy using both external and cloud copies.

Practical / learning evidence

A conversion ladder worksheet with at least five worked conversions, a four-technology comparison chart and a backup strategy paragraph. Submit both for marking.

Resources and preparation

An HDD, a CD or DVD, a flash drive and a memory card. Calculators for conversion work. Printed conversion worksheets. Offline route: physical media and worksheets. Warn learners not to insert unknown flash drives into laboratory machines.

Assessment for learning

Mark the working, not just the final answer, since a wrong answer from wrong work fails later questions. Check the comparison chart for four distinct technologies compared across all four criteria. Ask two learners to explain their capacity method aloud before collection.

Inclusion and homework

Provide a printed conversion ladder as a reference and reduce the worksheet to three items where time is short. Extend confident learners with a comparison of SSD and HDD for speed. Homework: find the storage capacity of any phone, memory card or computer you can access in gigabytes.