1. Lesson 4 – Cache, virtual and flash memory
GCSE Computing – Topic 2
Lesson 4 – Cache, virtual and flash memory
ASPIRE TO:
Discuss how changes in memory technologies are leading to innovative computer designs.
CHALLENGE TO:
Explain the use of virtual, cache and flash memory. 

2. Keywords
Flash Memory - Solid-state memory used as low cost secondary storage in portable devices. Virtual memory - A section of the hard disk used as if it were RAM to supplement the amount of main memory available to the computer. Used when there is not enough main memory to run the programs required.

3. Advantages / Disadvantages of Virtual Memory
Create this table in your book: Advantages Disadvantages Put these items in the correct column
You can run more applications at once
Less hard drive space for your use
It takes more time to switch between applications
You can run larger applications with less real RAM
You don't have buy more memory RAM
Applications run slower

4. Cache Memory - Recap
Cache memory is a small amount of very fast memory that is built into the CPU. Instructions and data that are in use by the CPU are copied from RAM into cache memory, along with the memory addresses.
If the CPU needs to access a memory address it first checks the cache memory to see if there is a match. If there is then it accesses the contents of the cache version.
Recap from previous lesson, do not need to make notes unless students want to.

5. Use the resource sheet to match the pairs.
How are changes in memory technologies leading to innovative computer designs?
Use the resource sheet to match the pairs.

6. Task
Answer exam questions. PIN mark each others work.

7. Exam style questions – possible answers
RAM stands for Random access memory while ROM stands for Read only memory. State 2 other differences between RAM and ROM. [2]
RAM is volatile, ROM isn’t
RAM is quicker to access than ROM
ROM can store larger amounts of data than RAM
The music department needs to transport 500 MP3 music files from school to students home. It would take too long to download so it has been suggested that secondary storage devices could be used.
What would be the best medium to use and why? [3]
Memory Stick – hold gigabytes of data and is easily portable
CD – as long as songs are still in MP4 format should fit on a CD or two
What is the minimum estimated capacity of the medium? [1]
Anywhere between 1.5gb and 3gb
Explain why mobile phones use solid state memory instead of hard drives. [4] Hint: think about portability, energy efficiency & reliability
Spinning parts inside a mobile device could easily lead to damaged hard disk
Hard disks must spin and use far more energy, thus decreasing battery life
If the phone is dropped, the disk is likely to break, either be scratched or damaged.

8. Plenary You have 60 seconds to tell your partner about: You must NOT:
COMPUTER MEMORY
You must NOT:
Hesitate
Stop talking until the 60 seconds are up
Repeat what you have already said