<Li> Synchronous / Asynchronous: This denotes if the memory is in sync with the system clock cycle or not </Li> <Li> Read / Write speed: This denotes the speed for the two key operations </Li> <Li> Access time (latency): This denotes the time it takes for the data to arrive on the data bus </Li> <Li> P / E Cycles (endurance): This is applicable only to Non-volatile memories . This denotes the number of program and erase cycles the memory can handle . </Li>

State two main types of semiconductor memories. explain it briefly