GATE CS 2014 Set 3 Q44 — Memory Hierarchy: Cache, Main Memory and Secondary Storage

To find the average memory access time (AMAT) for the given sequence of instructions, we first categorize the operations into Read and Write operations.

1. Categorizing the Operations

• Instruction Fetch: This is a read operation.
  Number of instruction fetches = $100$
• Memory Operand Read: This is a read operation.
  Number of operand reads = $60$
• Memory Operand Write: This is a write operation.
  Number of operand writes = $40$

Thus, we have:

• Total Read Operations ($N_R$): $100 + 60 = 160$
• Total Write Operations ($N_W$): $40$
• Total Operations ($N_{\text{total}}$): $160 + 40 = 200$

2. Calculating Average Access Times

Given the cache hit ratio ($h$) is $0.9$, the miss ratio ($m$) is $1 - 0.9 = 0.1$.

Average Read Access Time ($T_{R}$):

Average Write Access Time ($T_{W}$):

3. Calculating Overall Average Memory Access Time (AMAT)