Memory capacity of a RAM

Question

If a RAM has 32 bits in its MAR(memory address register) and its MDR (Memory data register) is 16 bits wide, then what is the capacity of RAM.

My probable solution is that it can address upto 2^32 locations.

Answer 1

Your solution is incorrect. The question is what the capacity is, not the number of addressable locations. Your answer should be measured in units of storage (e.g, bits, bytes, or their multiples).

Since this is clearly a homework problem, I'm not going to give an exact answer. But I will point you in the right direction by asking some additional questions:

• What is the memory data register used for? (Refer to your textbook if you're not sure.)

• What is the capacity of the memory data register? (The answer is in the question. Don't think about it too hard.)

• With that in mind, what is the capacity of the memory?

Answer 2

Yes, that sounds right. If a microprocessor or CPU has a memory address register with a size of 32 bits, it can access 2³² locations, as 32 binary bits used in combination allow you to handle 2³² different values starting from 0 to 4294967295 (2³² - 1).