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. 

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.

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

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.

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.

Task Answer exam questions. PIN mark each others work.

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.

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