Solution

The correct answer is A, B and D Only

Key Points

• A. It is slower than static RAM(SRAM) - This is correct because DRAM has longer access times than SRAM.
• B. Packing Density is higher than Static RAM (SRAM) - This is also correct. DRAM can fit more memory into a smaller space because it uses a single capacitor and transistor for each bit of data, while SRAM uses six transistors per bit.
• C. It is faster than static RAM(SRAM) - This is incorrect. SRAM is actually faster than DRAM because it does not need to refresh data like DRAM.
• D. It requires data refreshing - This is correct. DRAM uses capacitors to store each bit of data, and these capacitors gradually leak their charges over time. Because of this, DRAM requires periodic refreshing to maintain its data.

So the correct answer is A, B and D Only

Additional Information

• SRAM (Static Random Access Memory): SRAM retains its contents as long as power is applied to the system. It does not need to be refreshed like DRAM because it uses flip-flops, which are bistable or having two stable states, to store the data. Data in SRAM remains stable as long as the memory has power. SRAM is faster and more reliable than DRAM but it's also more expensive. Therefore, it's typically used for cache memory in a system.
• DRAM (Dynamic Random Access Memory): DRAM, on the other hand, needs to have its storage cells refreshed periodically or else it loses the data. This is because each cell in DRAM is made of a capacitor and a transistor and the capacitors can lose their charge over time. The dynamic nature of DRAM involves constant refreshing, which leads to slower data access rates compared to SRAM. However, DRAM is cheaper and has a higher density (more storage per unit area) than SRAM, so it is used as the main system memory in computers.