[STUDY] WHAT CACHE MEMORY IS BASED ON PC COMPUTERS

CACHE MEMORY

DEFINITIONS

1. A Cache Memory consists of a small, fast memory located between the CPU and main memory which takes advantage of the locality of access. Cache is used by the central processing unit of a computer to reduce the average time to access memory. Cache supplies the processor with the most recently accessed information or instructions.

Data and instructions that have been loaded into the cache can be accessed faster than that located in main memory. Cache Memory is special memory that operates much faster than SDRAM memory. It is also more expensive. It would be impractical to use this memory for the entire system both for reasons of expense and physical board and bus channel design requirements.

Cache memory lies between the microprocessor and the system RAM. It is used as a buffer to reduce the time of memory access. There are two levels to this memory called L1(level 1) and L2(level 2). The level 1 memory is a part of the microprocessor. The goal of an effective memory system is that the effective access time that the processor sees is very close to t0, where t0 is the access time of the cache. Most accesses that the processor makes to the cache are contained within this level. The achievement of this goal depends on many factors : the architecture of the processor, the behavioral properties of the programs being executed, and the size and organization of the cache.

DEFINITION

DEFINITION

2. A Cache Memory is a special very high speed memory used to increase the speed of processing by making current programs and data that needed processing readily available to the CPU at a rapid rate. The Cache Memory is designed to compensate for the speed difference between the main memory access time and processor logic clock cycle time.

DEFINITION

3. A Cache Memory is a temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data. A Cache has proven to be extremely effective in many areas of computing because access patterns in typical computer applications have locality of reference

USES OF CACHE MEMORY

>>> to compensate for the mismatch in operating speeds by employing an extremely fast, small cache between the CPU and main memory whose access time is close to processor logic clock cycle time.

>>> for storing segments of programs currently being executed in the CPU and temporal data frequency needed in the present calculations.

>>> to increase the performance rate of the computer by making programs and data available at rapid rate.