What is the main difference between main memory and external memory?

The main difference between main memory and external memory is: main memory is used to store programs and data that are to be used immediately. The access speed is fast, but the capacity is small and the price is expensive; external memory is used to store programs that are not used temporarily. And data, large capacity, low price, but slow access speed.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Memory is a memory component used to store programs and various data information. Memory can be divided into two categories: main memory (referred to as main memory or memory) and auxiliary memory (referred to as auxiliary memory or external memory). It is the main memory that directly exchanges information with the CPU.

Main memory is an important component of computer hardware. Its function is to store instructions and data, and can be directly accessed randomly by the central processing unit (CPU). Modern computers often adopt multi-level storage systems in order to improve performance while maintaining reasonable costs. That is, a cache memory with small storage capacity and high access speed, and a main memory with moderate storage capacity and access speed are essential. Main memory stores information according to address, and the access speed generally has nothing to do with the address. A 32-bit (bit) address can express a maximum memory address of 4GB. This is sufficient for most applications, but it is not enough for some extremely computationally intensive applications and extremely large databases, which requires a 64-bit structure.

External memory refers to storage other than computer memory and CPU cache. This type of storage can generally still save data after power is turned off. Common external memories include hard disks, floppy disks, optical disks, U disks, etc.

The difference between main memory and external memory

The most prominent feature of main memory is fast access speed, but small capacity and expensive price; the characteristic of external memory is capacity Large, low price, but slow access speed.

Main memory is used to store programs and data that are needed immediately; external memory is used to store programs and data that are not used temporarily. Information is frequently exchanged between internal memory and external memory.

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