Black and white Computer

Internal Memory  is the memory device that often use by Central Processing Unit (CPU) for the fast performance.However,the faster the performance the higher the cost of memory per bit. Internal Memory is volatile except the ROM. Cost per bit compare to external Memory is more expensive. Function of Internal memory is to  Temporarily store data and instructions that are being executed or will be executed by the CPU. Internal Memory can divided into 3 types: Register Cache Main Memory Register   located inside the processor. Each register typically holds a word of data (often 32 or 64 bits). Fastest of all forms of computer data storage but also most expensive. Cache Processor cache is an intermediate stage between ultra-fast registers and much slower main memory. It's introduced solely to increase performance of the computer. Most actively used information in the main memory is just duplicated in the cache memory, which is fas...

The following is the characteristic of Read Only Memory (ROM). Non-volatile(data remain even the power cut off) Mainly using in Embedded System Only can write the information once at time of manufacture Can only read the data but no write therefore call Read Only Memory It is directly accessible. Example of type: Programmable ROM Erasable Programmable ROM Electrically Erasable Programmable ROM  Cheaper than RAM Read rate is slow than RAM The logic value is 0 if the transistor is connected to ground like the picture above. READ OPERATION First ,the word line is activate to close the transistor .After the transistor is close,the voltage on the bit line drop near zero if there is a connection between the transistor and ground,else the bit line remain at high voltage which mean a logic value 1. The sense circuit at the end of the bit line generates the proper output values.