Question

Which type of RAM is generally used as the main memory in modern PCs and requires periodic refreshing?

• A. Flash
• B. ROM
• C. DRAM
• D. SRAM

Hint:

Remember: \[ \text{DRAM} = \text{Dynamic} = \text{Needs Refreshing} \] \[ \text{SRAM} = \text{Static} = \text{No Refreshing} \] DRAM is generally used as main memory, while SRAM is commonly used for cache memory.

Answer 1

The Correct Option is C

Concept: Computer memory is used to store data and instructions required by the CPU. RAM (Random Access Memory) is volatile memory, meaning its contents are lost when power is switched off. The two major types of RAM are:
• DRAM (Dynamic RAM)
• SRAM (Static RAM) DRAM stores data in capacitors. Since capacitors gradually lose their charge, the stored information must be refreshed periodically to retain data. SRAM uses flip-flops and does not require refreshing, but it is more expensive and is generally used for cache memory.

Step 1: Understand the meaning of periodic refreshing.
When data is stored in DRAM cells, electrical charge slowly leaks away. To prevent loss of information, the memory controller refreshes the contents thousands of times every second.

Step 2: Analyze each option.

• Flash Memory – Non-volatile memory used in SSDs and pen drives.
• ROM – Read Only Memory; does not require refreshing.
• DRAM – Requires periodic refreshing.
• SRAM – Does not require refreshing.

Step 3: Identify the memory used as main memory.
Modern computers use DRAM as their primary main memory because it provides large storage capacity at relatively low cost. \[ \boxed{\text{Main Memory} = \text{DRAM}} \] Therefore, the correct answer is: \[ \boxed{\text{DRAM}} \] Hence, option (C) is correct.