SS 2 First Term

Lesson objectives

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

1. Define primary memory and secondary memory in their own words.
2. Name three types of RAM and state volatility for each.
3. Explain caching as temporary faster access to frequently used data.
4. Compare SRAM and DRAM on speed and cost.
5. Map a program execution path onto main memory stages.

Key vocabulary

• Memory: working space holding programs and data currently in use.
• Main memory: memory inside the CPU accessible directly.
• Secondary memory: storage kept off the CPU bus.
• Volatile: loses contents when power is removed.
• SRAM: static RAM holding data without refresh cycles.
• DRAM: dynamic RAM requiring regular refreshes.
• Cache: very fast temporary storage nearby the CPU.
• Refresh cycle: repeated reads keeping DRAM data current.
• Execution path: the sequence of memory locations accessed during a run.

Common misconceptions

• "RAM holds my files permanently." RAM holds work in progress and clears at shutdown.
• "Cache stores permanent data." Cache is temporary and cleared once the data moves elsewhere.
• "SRAM and DRAM do the same things." SRAM is faster but more expensive than DRAM.

Teacher activities

1. Starter: ask where your running spreadsheet data sits temporarily while you use it.
2. Define main and secondary memory with one example each.
3. Name three types of RAM and note their volatility.
4. Explain caching as faster access for frequently used data.
5. Compare SRAM and DRAM on speed and cost with a simple analogy.
6. Map a simple program execution onto main memory stages.

Student activities

1. Answer the starter and identify main versus secondary memory.
2. Define main and secondary memory in their own words.
3. Name three types of RAM and state volatility for each in one sentence.
4. Explain caching in one paragraph tied to frequent access.
5. Compare SRAM and DRAM on speed and cost with brief reasoning.
6. Map a program execution onto main memory stages showing data movement.

Practical / learning evidence

A three-RAM type chart with volatility and a SRAM versus DRAM comparison, plus a one-page caching explanation. Hand in both for marking.

Resources and preparation

Printed charts, blank diagrams and sample program execution traces. Offline route: paper versions, no device needed. Display any hardware carefully and keep tools out of reach.

Assessment for learning

Inspect the three-RAM chart for correct volatile states. Mark the SRAM versus DRAM comparison for correct tradeoffs. Check the caching explanation for a sensible analogy. Flag any learner who says cache stores files permanently.

Inclusion and homework

Provide the three-RAM chart prefilled for learners who need scaffolding and allow oral comparison. Extend confident learners with five RAM types and a four-stage execution map. Homework: name two places in your school lab that use cache and state why they need it.