ITPEC FE Morning April 2023 Question 13

Write Back vs Write Through — cache write policies.

Two main cache write strategies:

• •Write back — data is written only to cache; main memory is updated later (when the cache line is evicted)
• •Write through — data is written to both cache and main memory simultaneously

Write back minimizes write operations to main memory but requires a dirty bit to track modified lines.

Why not others:
- (a) Overlay — a memory management technique for loading program segments, unrelated to cache
- (c) Write protected — prevents writing to a memory region; not a cache policy
- (d) Write through — writes to main memory on every write; reliable but slower

Key rule: "Write back = lazy writes (update RAM later); Write through = eager writes (update RAM immediately)."

AI-generated — may contain errors