What is the purpose of including a cache memory even after having a main memory and a virtual memory? What are the advantages of the cache memory? How is it better than the other two memory modules?
Need Of a Cache Memory And Its Features
Cache is a small memory possessing high speed that contains within it the most recently accessed parts of the main memory. The cache is faster because of its size and the technology used to build it. It improves the performance of the system. However, it cannot handle very large data as it has SRAM. Thus, the high speed of cache makes it an important requirement.
Need Of a Cache Memory And Its Features
CPU memory is the other term for cache memory. It is a kind of RAM or random access memory that a processor can utilize much quicker than accessing a normal physical RAM. It is basically designed to store program instructions that are often referenced by software during operation. Because of fast access to these instructions, the overall performance of a program is increased.
As the processor processes data, the first place where it looks for instructions is the cache memory. If the instructions are there, it will no longer have to perform a lengthier reading of data from bigger memory or from other data storage devices.
Nearly all programs use a handful of resources as soon as they have been started and operated for a time basically because regularly re-referenced instructions tend to be cached. This is why the performance of computers with slower processors but larger caches tend to be faster compared to the performance of computers with faster processors but more limited cache space. Cache memory is fast but expensive.
Cache memory is usually classified according to levels that define its accessibility and closeness to the processor and they are the following:
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* Level 1 cache (L1) – this cache level is tremendously fast but quite small and is normally embedded in the processor chip.
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* Level 2 cache (L2) – this cache level is frequently larger than L1 and may be located or integrated on the processor or on a separate chip or co-processor with a high-speed alternative system bus interconnecting the CPU to the cache so that it will not be slowed down by traffic on the main system bus.
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* Level 3 cache (L3) – this cache level is normally a specialized memory designed to enhance the performance of L1 and L2. It can be considerably slower than L1 and L2 but is normally double the speed of the physical RAM.
