Register,cache,memory PDF

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great notes for cache memory register...

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Registers, Cache, and Memory are all temporary storage to store code and data. How fast these locations can be accessed makes the difference (in their location, size and cost). 1. CPU consists of Control Unit, ALU and Registers. So, the registers are placed within the same device as CU and ALU. In terms of access speed: "registers are the fastest." It is expensive to have many registers withing the CPU as this makes CPU bulky, consuming more energy. 2. Memory (or main memory) is a large temporary storage, and CPU needs to use (address and data) Bus to access the contents. Bus is a collection of wires connecting CPU, Memory and I/O devices. So, memory is the slowest temporary storage. Usually, it is composed of many IC chips arranged in "Memory Cards" that you can find in your PC motherboard. It is not so expensive. 3. Cache is a part of memory "built using expensive and fast IC chips". So, cache is a part of memory, but faster to access compared to memory. Now, there are two kinds of cache found in modern computer systems, Level 1 and Level 2 caches. So, the cache which is a part of the memory address space is called L2 cache. So, we have been talking about L2 cache until now. And L1 cache is placed inside the CPU packaging (i.e. within the same device). And, obviously, L1 cache is smaller in size compared to L2 cache. So, in terms of speed (high to Low): Registers->L1 Cache-> L2 Cache-> Main Memory So, in terms of cost (high to Low): Registers->L1 Cache-> L2 Cache-> Main Memory So, in terms of size that is usually found in computer systems (Low to High): Registers>L1 Cache-> L2 Cache-> Main Memory...