How do you solve the process of data exchange between external memory and memory?

The connection between the various components of the computer is realized through the flow of information, and there are two kinds of information flow, one is the data flow and the other is the control flow. The data flow refers to the raw data, programs and various operation results, and the control flow refers to the request signals sent by each component to the controller and the control signal sent by the controller to each component.

There are four types of this:

1. Direct program control mode: that is, the user process directly controls the information transmission between the memory or CPU and the peripheral equipment. In this way, the controllers are all user processes.

2. Interrupt control mode: It is used to control the data transmission between peripheral devices and memory and CPU. This approach requires that there is a corresponding interrupt request line between the CPU and the device (or controller), and that the corresponding interrupt allowed bit is in the control state register of the device controller.

3. DMA mode: also known as direct access mode. The basic idea is to open up a direct data exchange channel between peripherals and memory.

4. Channel mode: Similar to DMA mode, it is also a memory-centric way to realize direct exchange of data between devices and memory.

Hello, glad to answer for you, the CPU exchanges information with memory and external memory through the motherboard. The motherboard is the largest circuit board in the computer system, and its English name is "mainboard" or "motherboard", abbreviated as M B. The motherboard is covered with various electronic components, slots, interfaces, etc.

It provides mounting sockets (slots) for CPU, memory, and cards for various functions (sound, graph, communication, network, TV, SCSI, etc.). It provides interfaces for various magnetic, optical storage devices, printing and scanning equipment, as well as digital cameras, cameras, "cats" (modem) and other communication equipment. The control of system memory, storage devices, and other IO devices must be done through the motherboard during the normal operation of the computer, so the overall speed and stability of the computer depends to a considerable extent on the performance of the motherboard.

Extended information: The CPU bus is the fastest bus in a computer system and is the heart of the chipset and motherboard. People usually refer to the local bus directly connected to the CPU as the CPU bus or internal bus, and those local buses connected to various general expansion slots are called system buses or external buses.

In CPUs with a relatively single internal structure, only a set of data transmission buses, i.e., CPU internal buses, are often set up to connect the registers inside the CPU with arithmetic logic operation components, so this type of bus can also be called ALU bus. The bus within the component uses a set of buses to connect each chip together, so it can be called the intra-component bus, which generally includes two sets of lines: the address line and the data line. The system bus refers to the line that connects the various components inside the system, and is the basis for connecting the whole system together; The bus outside the system is the basic line that connects the computer and other devices together.