The relationship between computer structure and CPU, memory and hard disk

As mentioned earlier, the father of computer-- von Neumann presents five parts of the computer: input device, output device, memory, arithmetic device and controller.

Let's take a look at our computer now: Keyboard mouse, monitor, chassis, audio and so on.

Here the monitor for the older CRT display, now generally successful LCD display.

We think about, when we play computer, we use the keyboard mouse to operate the computer, we chat with other people QQ, the mouse can help us select the chat, open the Chat window, the keyboard is responsible for typing, help us enter the content of the chat.

When we operate the keyboard and mouse, we are actually telling the computer to do something. Our keyboard and mouse are called input devices.

Input device: A device that enters data and information into a computer. except the keyboard. In addition to the keyboard and mouse, other input devices include touchpad, microphone, camera, gamepad, scanner, etc.

The monitor is used to show us the screen, display the content, the speaker plays music to us, we call them the output device.

Output device: A device that outputs information from a computer to a user. Commonly used input devices are: monitors, speakers, printers, projectors and so on

We buy computer, if only keyboard mouse, monitor, speaker, we can play computer? Definitely not. So in fact, the computer chassis is the real work of the device, input just used to let us and the computer chassis to do the interaction.

What's inside the chassis? Let's take a look at the following picture:

Let's see what the parts here are for.

Motherboard: Connect all other equipment, is the carrier of other equipment, motherboard is mainly for CPU, memory, graphics card, hard disk, etc. to provide a platform, equivalent to the body's torso, associated with each organ.

CPU: The abbreviation of the central Processing unit (cntral pocessing Uit), also called the processor, is the computing core and the control core of the computer. People rely on the brain to think, computers rely on the CPU to calculate, control. Let the various parts of the computer work smoothly, play the role of coordination and control.

Hard disk: The device that stores data such as information and software, has the characteristics of large capacity and no loss of power-off data. It is also known as the "Data Warehouse".

Memory: 1. Responsible for data exchange processing between data and CPU on hardware such as hard disk, 2. Cache temporary data in the system. 3. Data loss after power failure.

Video card: The display wants to render the screen, the video card is the key. In simple terms, it is responsible for displaying all information on the display. For example, it is like a human eye, without it, the computer will not be able to drive the formation of images. Graphics performance is good, the computer graphics processing capacity is high, especially in the game to find this more (so many games will require graphics card performance). For gamers, it's a good idea to choose a standalone video card. However, if you do not play a large game, the CPU built-in core graphics will basically meet the requirements. Disadvantage: The system power consumption has increased, heat is also large, additional purchase

Power: the voltage 220 volts of the mains converted to low voltage, and then sent to the motherboard and various hardware! Power supply! The computer needs power, and the power supply is for this, it can also say that it provides all the power for the computer. The power supply determines the stability of the computer. It is similar to the human heart function and is the core of the power supply.

Network card: Let us surf the Internet, generally integrated on the motherboard.

Other..........................

Said so much, in fact, the most important equipment is what? CPU, hard disk, memory.

now let's take a look at the relationship between CPU, hard disk, and memory.

First, let's recall the role of the three:

CPU: Is the computer's computing core and control core, so that the various parts of the computer work smoothly, play a role in coordination and control.
Hard disk: The device that stores data such as information and software, has the characteristics of large capacity and no loss of power-off data. It is also known as the "Data Warehouse".
Memory: 1. Responsible for data exchange processing between data and CPU on hardware such as hard disk, 2. Cache temporary data in the system. 3. Data loss after power failure.

Then, let's look at how the program executes.

When we open QQ on the computer (right-open or double-click the QQ icon), in fact, through the mouse (input device) to the CPU sent a command, the CPU received this command, the QQ program from the hard disk is loaded into memory (loading without the processor, directly from the hard drive loader into memory), When the load is complete, the CPU begins to execute the QQ program. After the program executes, the CPU can let the QQ program display on our monitor. That is, you see the QQ program to run up. If this time, you use QQ to intercept a picture of the screen, then this picture will be saved to the memory, in the absence of the screenshot state, you can write on this picture, draw lines, and so you right-click on the picture, the picture will be saved to the hard disk.

By understanding how a program works, we can see how the three work.

Some people may not understand that if the program is executed in this way, then why does the CPU not directly execute the program in the hard disk, rather than put the program into memory after the execution?

There is a reason for this. Let's take a look at some pictures:

Better business with mechanical HDD: General SSD:

Memory read and write speed:

As we can see, the memory accesses data 10 times times faster than the hard disk, in some environments, the speed gap between the hard disk and memory may be greater.

And the CPU speed than memory does not know how many times faster. When we put the program from the hard disk into memory, the CPU runs the program directly in memory, which is much faster than the CPU running the program directly on the hard disk.

Memory solves the problem that some CPUs are running too fast and hard disk data accesses too slowly. Improves the speed of our computers.

Memory is like a "high-speed lane" in general, the data from the slow transmission of the hard drive through this high-speed lane to the CPU for processing!

However, the memory is stored on-line (once the power loss data disappears), and the capacity is limited, so long time to save the program or data need to use the hard disk.

In fact, memory here has two functions:

1. Save the data read from the hard disk and provide it to the CPU

2. Save some of the CPU's temporary execution results so that the CPU is next used or saved to the hard disk

The relationship between three people:

In short, the hard disk is used to store our programs and data, when we run the program, the CPU first to accept our command, after the CPU is to tell the hard disk, I want to run your stored program A, you put program A to the memory. CPU to memory said, I let the hard drive to send program A to you here, you save it. After the program A is completely sent to memory. The CPU starts executing program a.

The process is like above, and we're going to cite an example that is close to our lives.

If the hard disk is likened to a large warehouse, the CPU analogy to the processing workshop, then the memory is a temporary small warehouse. From the distance, the memory and CPU distance is shorter than the memory-to-CPU distance and the hard disk-to-memory distance.

Hard drives (large warehouses) are used to store the raw materials used in the workshop and the products that are ultimately produced. The warehouse is too large to remove raw materials and storage items too slow and time consuming.

Memory (Temporary small warehouse): Raw materials will be placed here, small warehouses, you can quickly find the required raw materials or products.

CPU (Workshop): Get raw material from memory (small warehouse), produce goods. Intermediate will have semi-finished products, semi-finished products can be placed in memory (small warehouse).

In this way, the production speed of the workshop will be increased.

Reference diagram

Reference: CMU, Google pictures

The relationship between computer structure and CPU, memory and hard disk