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Looking at the green characters displayed in the black display, Lin Hong was no longer as dazed as before this time.

He now knew that the top display was the name and version number of the operating system in the computer.

Lin Hong's apple_ii is equipped with the operating system, which is the latest version of the apple_dos operating systemv3.3, and before that, there were v3.1 and v3.2, but the previous version was not so powerful, and it was based on tape storage devices. This version is also the most famous and widely used version of apple_dos. Later, the Apple computer, the system has been replaced with a pro_dos, which is specially customized by Microsoft.

apple_dos was Apple's first disk-based system, and it was natural that Wozniak, a genius computer engineer, was involved in writing a large part of the code.

Looking at the beating green "[" symbol on the monitor, Lin Hong stretched out his two index fingers, and then lowered his head to look at the keys on the keyboard, on the keyboard, there were corresponding letters printed, he pressed a few keys slowly and hard, and the word "catalog" appeared on the monitor slowly and with difficulty.

Lin Hong didn't understand why the letters of the keyboard were arranged like this, and there was such a difference between A and B.

Much later, he learned that this keyboard layout, known as the "Qwerty Corti keyboard", had been invented in the mid-nineteenth century and was originally designed for mechanical typewriters.

The reason for this layout is that the structure of the mechanical typewriter is that the structure of the lead lever determines that when two lead characters close to each other are pressed at the same time, they will be stuck, but the same problem will not occur when the two lead characters are far apart. Later, after the advent of computers, this layout continued.

After typing this command with difficulty, Lin Hong pressed the Enter key, and finally there was a change on the monitor, and a long list was displayed at once, this was a directory display command, and these contents were exactly what was contained in the disk.

Seeing this result, Lin Hong had a happy smile on his face.

It was the first computer command he entered, and although it was simple, it still made him feel excited and excited.

Looking at this computer under its own control, and then starting to react, this sense of conquest that everything is under your control is difficult to describe in words.

This may be the main reason why boys like all kinds of toys and all kinds of machines.

Next, Lin Hong began to experiment with all the commands one by one according to what was told in the reference book, and then observed the results. Looking at the various information that kept flashing on the monitor, the sense of accomplishment in his heart was beyond words.

apple_dos operating system is relatively simple, and there are only a few system commands over and over again, such as the "catalog" used by Lin Hong before, which means "directory" in English, and the function is to display the file directories in the disk. There is also "intbasic", which is to enter the intager_basic language programming state, and after typing this command, you can start writing code for programming.

The so-called system commands are actually small pieces of software. The operating system generally comes with some common software, which is bound to the system, which becomes the system command.

If you are not satisfied with these commands in the system and feel that you can implement the same function in a better way, you can also write a small tool like this yourself, and then replace the original software.

After Lin Hong played with the system commands for a while, he began to practice the programming of the basic language.

The language of computer programming, as the name suggests, is the language between a person and a computer. It was invented to be easily understood. When computers were first invented, those fierce people directly used machine language to operate computers.

Programming languages can be broadly divided into low-level and high-level languages, which in turn include machine language and assembly language.

The low level here does not mean that the language is not very powerful, but it is distinguished by the difficulty that beginners can master. In fact, lower-level languages are more powerful and can be written more efficiently.

High-level languages are languages that came later, in order to make people better understand, and they are very close to the words that people usually write.

Basic is a kind of high-level language, which is the abbreviation of "beginner's_all-purpose_symbolic_instruction_code", which Chinese means "beginner's omnidirectional symbolic instruction code".

This language is a high-level language created by two computer scientists in the United States specifically for college students on campus, with the goal of making it easy for college students to use computers. Although the initial basic only had a few dozen sentences, because it was relatively easy to learn at the time, it quickly moved from the campus to the society, and became the preferred language for beginners to learn computer programming.

Later, computer engineers and experts at some computer companies expanded Basic to make Basic more complex, and Apple's integer_basic was developed on this basis by Wozniak and two other colleagues.

For beginners, the basic language is clearly the best choice, and it was also the most popular programming language in the eighties.

Lin Hong typed down two lines of code directly under the command prompt:

01_print_“hello,world!”

02_end

Then, he typed in the "run" command directly on the third line.

I saw the next line, and immediately there was a "hello, world!" contents.

“hello，world！” Lin Hong clenched his fist very happily and read it aloud according to the English in the monitor.

Although there are already such interface results in the manual, the feeling of his own operation is different.

This is just an extremely simple small program, no matter what language you learn, when every beginner learns programming, basically the first program is this "hello, world", which has basically become a habit of programmers.

"Hello, World!"

It's such a simple program that beginners can easily understand it even without any foundation, but it's not pale, it has the distinctive characteristics of a programming language, embodying the most basic ideas and characteristics of a programming language.

This seems to be a cry for beginners to the computer world, marking their entry into this wonderful artificial world, including the announcement and the joy of beginners experiencing the success of writing their first computer program.

Lin Hong's mood at the moment is like this, he feels that these two simple words just say what he is thinking at the moment.

The origin of "hello, world" can be traced back to 1972, when brian_kernighan, a famous researcher at Bell Labs, first used this paradigm when he wrote "Tutorials and Tutorials for B (the predecessor of C)", and later used this paradigm again in C language tutorials, and since then, it has been widely circulated.

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