tailieunhanh - Bài giảng Computer Organization and Architecture: Chapter 4

Bài giảng Computer Organization and Architecture: Chapter 4 với nội dung chính là Cache Memory sẽ giới thiệu tới các bạn các vấn đề về: Location; Capacity; Unit of transfer; Access method; Performance; Physical type; Physical characteristics; Organisation. | William Stallings Computer Organization and Architecture 6th Edition Chapter 4 Cache Memory Characteristics Location Capacity Unit of transfer Access method Performance Physical type Physical characteristics Organisation Location CPU Internal External Capacity Word size The natural unit of organization Number of words or Bytes Unit of Transfer Internal Usually governed by data bus width External Usually a block which is much larger than a word Addressable unit Smallest location which can be uniquely addressed Word internally Cluster on M$ disks Access Methods (1) Sequential Start at the beginning and read through in order Access time depends on location of data and previous location . tape Direct Individual blocks have unique address Access is by jumping to vicinity plus sequential search Access time depends on location and previous location . disk Access Methods (2) Random Individual addresses identify locations exactly Access time is independent of . | William Stallings Computer Organization and Architecture 6th Edition Chapter 4 Cache Memory Characteristics Location Capacity Unit of transfer Access method Performance Physical type Physical characteristics Organisation Location CPU Internal External Capacity Word size The natural unit of organization Number of words or Bytes Unit of Transfer Internal Usually governed by data bus width External Usually a block which is much larger than a word Addressable unit Smallest location which can be uniquely addressed Word internally Cluster on M$ disks Access Methods (1) Sequential Start at the beginning and read through in order Access time depends on location of data and previous location . tape Direct Individual blocks have unique address Access is by jumping to vicinity plus sequential search Access time depends on location and previous location . disk Access Methods (2) Random Individual addresses identify locations exactly Access time is independent of location or previous access . RAM Associative Data is located by a comparison with contents of a portion of the store Access time is independent of location or previous access . cache Memory Hierarchy Registers In CPU Internal or Main memory May include one or more levels of cache “RAM” External memory Backing store Memory Hierarchy - Diagram Performance Access time Time between presenting the address and getting the valid data Memory Cycle time Time may be required for the memory to “recover” before next access Cycle time is access + recovery Transfer Rate Rate at which data can be moved Physical Types Semiconductor RAM Magnetic Disk & Tape Optical CD & DVD Others Bubble Hologram Physical Characteristics Decay Volatility Erasable Power consumption Organisation Physical arrangement of bits into words Not always obvious . interleaved The Bottom Line How much? Capacity How fast? Time is money How expensive? Hierarchy List Registers L1 Cache L2 Cache .