Introduction to the operating system and programming language

• Operating system Introduction
• Programming language classification

The essence of operating system is a kind of software control computer hardware.

We usually boot after the ROM chip self-test is normal, normal, it will notify the running BIOS system inside the command, the hard disk on the operating system data transfer to memory (RAM), from RAM to the CPU, the last window operating system began to run, by the operating system management, operation, Control each computer's hardware.

Why do we have to program it? What is the purpose of programming? I think a lot of small white may also be very popular with this problem, but also some people say, not just to control the computer, so the answer is also right; let me share what I understand: human beings want computers to work for human beings, thus liberating the human workforce, so that by some computer language grammar and format, The heart wants to let the computer work to write the document, these files are our commonly known procedure, is the programming goal.

So let's start with an example of how to enter and save a resume on a USB flash drive:

1. Plug the USB flash drive into the computer interface. (The USB stick is part of the computer's hardware at the moment)
2. Open the interface (press the power button, because the computer's startup is composed of a lot of programs, but you press power on while the hardware resources and software resources at the same time running, these complex programs to start the premise of the human to encapsulate them into a simple interface)
3. Start the operating system (the operating system starts to control the work of the computer hardware)
4. Create a text file (the file is a virtual unit, he is not a physical object, it is established after opening the operating system to reflect the interface)
5. Enter the relevant content on the file (that is, enter it on RAM)
6. Save file (last transferred from RAM to hard disk)

In summary, in fact, the input of the file is to let the operating system control hardware operation.

In order to deepen the image, one more example is the launch of QQ (application):

• Double-click the shortcut (send instructions to the operating system)
• Handing the executable file path to the operating system

• The operating system controls the hard drive to find out where the files are stored
• Transfer the file data to the memory to read
• Control the CPU to run the memory in the file program after the operation
• The QQ program is launched on the display.

Human beings want to work with the command computer, the most direct way is to communicate with, say the computer can listen to understand words. However, computer language is actually binary system, so-called binary system is (0 1) Two digital composition, that is, high and low frequency, the lower the frequency is 0, the higher the frequency is 1;

• The advantage is fast execution;
• The disadvantage is that the development efficiency is slow.

With the progress of mankind, human invented the assembly language.

• The advantage is that you no longer need to remember binary (computer language)
• The disadvantage is that the execution is not as high as the machine language; it still needs to be translated into binary to operate the computer, and to master the hardware control of each program.

Further development, human civilization after the progress, people have invented a high-level language (Python PHP C + + Jave) These are human popular language, than assembly language to be simple, do not have to study the control hardware, through translation can translate simple language into binary language, but the current speed is almost , so AH execution efficiency is not appropriate and consideration, the main consideration of development efficiency, Python is currently the most popular programming language, the reason is that its own development efficiency quickly, can create more value.

Introduction to the operating system and programming language