The difference between memory and hard disk


Many computer Xiaobai still have questions, that is, what is the difference between memory and hard disk? Why is the same 300 yuan, buy memory can only buy 8GB capacity, and hard disk can buy more than 250GB.


Memory is also called internal memory. You can understand it as a transfer station for the exchange of hard disk data and CPU data. When we open software or documents, your files will be copied from the hard disk to the memory, and then the CPU will exchange data with the memory. This is because the read and write speed of memory is much faster than that of hard disk. You can even regard CPU as emperor, memory as eunuch and hard disk as you. You want to submit a memorial to the emperor for approval. First, you need to submit the memorial to the eunuch, who will hand it to the emperor.


The memory commonly used in our computers is called dynamic random access semiconductor memoryDRAM, belonging to temporary storage. Take out a piece of memory. We can see that there are several black squares on the memory, which we usually call particles. Due to the characteristics of DRAM, when the memory is powered off, the data stored in DRAM will be lost, which is also the reason why the data in the memory will be lost after we shut down.


In addition to the memory in the computer, we often hear the term “CPU cache”. In fact, “CPU cache” is also a kind of memory, which is called static random access semiconductor memory, also known asSRAM, the price is very expensive, which is one reason why the CPU cache capacity is relatively small at present. A 36mb SRAM particle on the market costs more than 300 yuan. The hard disk belongs to external memory. It can store data for a long time without being interrupted, and the storage capacity is relatively large.