The main function of memory is to store programs and all kinds of data, and can complete the access of programs or data at high speed and automatically in the process of computer operation. Memory is a device with "memory" function. It uses physical devices with two stable states to store information. These devices are also called memory element memory: devices for storing programs and data. Memory bit: a storage unit for storing a binary digit, which is the smallest storage unit of memory, or memory unit. Memory word: when a number (N binary bits) is stored or taken out as a whole, Called storage word storage unit: several memory units storing a storage word form a storage unit storage body: a collection of a large number of storage units form a storage body storage unit address: number word address of the storage unit: address the storage unit by word, byte address: address the storage unit by byte.