1. Primary Storage The Triplets – ROM & RAM & Cache

2. Intro History Travel Cache ROM RAM

3. History Vacuum Tube Transistor SRAM – Static RAM – 1-bit per cell – No refresh - fast DRAM – Dynamic RAM – More compact – Need refresh – slows speed

4. History Vacuum Tubes to Transitors – Original Memory modules

5. History SDR SDRAM – Now obsolete – PC 100 & PC-133 – Computes on 16Bit per clock cycle

6. History DDR - Old – Double clock speed – 100, 133, 166 and 200 MHz

7. History DDR2 – Still Used – Double clock speed;about 2-5% gain over DDR – 400, 533, 667, 800, & 1066 MHz

8. History DDR3 – 2008 and beyond – More Speed – 1066, 1333, 1600, 1800, & 2000 MHz

9. History SIMM – Single In-Line Memory Module 30-pin 72-pin DIMM – Dual In-Line Memory Module 72-pin to 288-pin DDR – DDR4

10. Travel

11. Cache On CPU – FAST!!!! Between 5% and 100% of CPU speed – Expensive – Limited space Different from registers – Not connected to CU or A/LU

12. ROM Boot Constant instructions

13. RAM Main memory Slower than cache – Approx 1% of CPU speed Cheaper than cache Easy to expand CPU can change Addressed