Explanation
1. Main Concept: Locality of Reference
Cache memory isliye kaam karti hai kyunki CPU aksar unhi memory locations ko baar-baar access karta hai jo ek dusre ke paas hoti hain ya jo hal hi mein use hui hain.
Iska relation Hit Ratio (h) se hota hai:
h=Total Memory RequestsCache Hits
2. Effective Access Time (EAT) Equation
Cache memory system ki average speed badha deti hai. Iska formula niche diya gaya hai:
Yahan:
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h = Hit Ratio (Locality of Reference jitni achi hogi, h utna zyada hoga).
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C = Cache access time.
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M = Main memory access time.
Kyunki C≪M, isliye high locality hone par EAT bohot kam ho jata hai.
3. Types of Locality
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Temporal Locality: Agar koi data abhi use hua hai, toh uske jald hi phir se use hone ki probability zyada hoti hai.
Probability(Datat)≈Probability(Datat+Δt)
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Spatial Locality: Agar koi data location X use hui hai, toh uske paas wali location X+1 ke use hone ki probability zyada hoti hai.
Answer: Cache memory ka idea Locality of Reference par based hai.
