The cache is used to store the tag field whereas the rest is stored in the main memory. An address space is split into two parts index field and a tag field. If a line is previously taken up by a memory block when a new block needs to be loaded, the old block is trashed. In Direct mapping, assigne each memory block to a specific line in the cache. The simplest technique, known as direct mapping, maps each block of main memory into only one possible cache line. There are three different types of mapping used for the purpose of cache memory which are as follows: Direct mapping, Associative mapping, and Set-Associative mapping. We can improve Cache performance using higher cache block size, higher associativity, reduce miss rate, reduce miss penalty, and reduce the time to hit in the cache. The performance of cache memory is frequently measured in terms of a quantity called Hit ratio. For a cache miss, the cache allocates a new entry and copies in data from main memory, then the request is fulfilled from the contents of the cache. If the processor does not find the memory location in the cache, a cache miss has occurred.If the processor finds that the memory location is in the cache, a cache hit has occurred and data is read from cache.When the processor needs to read or write a location in main memory, it first checks for a corresponding entry in the cache. It is external memory which is not as fast as main memory but data stays permanently in this memory. It is small in size and once power is off data no longer stays in this memory. It is memory on which computer works currently. It is the fastest memory which has faster access time where data is temporarily stored for faster access. Most commonly used register is accumulator, Program counter, address register etc. It is a type of memory in which data is stored and accepted that are immediately stored in CPU. ISRO CS Syllabus for Scientist/Engineer Exam.ISRO CS Original Papers and Official Keys.GATE CS Original Papers and Official Keys.
0 kommentar(er)
