CHAPTER

1. 6 CHAPTER THE SYSTEM UNIT

2. Competencies • Details about memory • Memory Classification Bases • Cache Memory • Virtual Memory

3. Quiz03 • Next Lecture – (Lecture #13) • Contents: • Chapter 4 – The System Unit • Lecture Slides- #10 - #12

4. Memory Classification Bases • Reading/ Writing Capability • Read Only Memory • Read/ Write Memory • Data Access Mechanism • Sequential Access Memory • Random Access Memory

5. … Memory Classification Bases • Volatility of Data • No Data Loss without Electricity (Non-volatile Memory) • Data loses without electricity (Volatile Memory) • Data can be changed and be permanently saved once changed (CMOS Memory) • Speed of Access • Cache Memory (Very high accessing speed)

6. Memory • Holding area for data, instructions, and information • Types of memory chips • RAM – holds programs and data • ROM – fixed start-up instructions • CMOS – flexible start-up instructions

7. RAM • Random Access Memory • Primary Memory of a computer • Data and Program needs to be loaded for processing • Any memory location can be accessed randomly • Volatile storage • Uses Cache support for increased efficiency • Flash RAM – Non-volatile/ portable

8. ROM • Read-only memory • Firmware • Cannot be changed by the user • Start-up instructions, keyboard control capabilities

9. CMOS • Complementary metal-oxide semiconductor • Flexible and expandable • Startup information • Non-volatile • Its contents may be updated

10. ….The Memory (More Concepts) • Virtual Memory • A technique used to make huge programs run on small memory size computers • A huge program is divided into many portions • Each portion could be adjusted inside the RAM • Program is then run by loading only the needed portion from hard disk • Operating System (OS-win98) is the one who is taking care of this transparently. • Effect: The program runs slowly

11. … The Memory (More Concepts)

12. Memory Capacity