Simple core computing basics
(Ps: getting started with small white dot)
First, computer composition principle
1. What is the computer
Computer (Computer), commonly known as a computer, a computer unit for calculating a high-speed modern, numerical calculations may be performed, but also can be logically calculated, further having a memory function. Is a modern intelligent electronic devices capable of running in accordance with the automatic, high-speed processing of massive data. Hardware and software system components, the computer did not install any software called bare metal. Can be divided into supercomputers, industrial control computers, network computers, personal computers, embedded computers five categories, more advanced computers have biological computers, computer photon, a quantum computer.
2. Why use a computer
The computer is a way to help humans perform some tasks can not be completed ordinary human tools invented, corresponding to the human slaves.
3. The five components of the computer
Controller : command and control system of the computer
Operator : a computer operation system, comprising logic and arithmetic operations
(Ps: a computer controller is the + operator central processing unit: CPU, corresponding to human brain)
Memory : local computer for storing data, and a hard disk into memory.
Memory : access speed, but not permanently store data, power that is loss of data.
HDD : hard disk drives and solid state current is divided into two kinds of mechanical hard drive, solid state disk access faster than mechanical hard drive, but the memory is relative to the access speed is very slow, but without damage to the hard drive permanently save data.
Input device : receiving device outside the computer data, such as a keyboard, mouse, camera, microphone and the like.
Output devices : computer output data to the outside apparatus, such as a display, a printer, audio.
(Ps: input and output devices may be referred to as I / 0 device)
4. computer's operating system
上面的五大组成部分指的是计算机硬件系统里面的五大重要组成部分，而计算机除了硬件系统还有软件系统，软件系统又分为系统软件和应用软件，其中操作系统就属于系统软件部分。简单来说操作系统主要将计算机硬件的各种复杂的接口封装起来，便于程序员开发程序以及便于用户通过应用软件方便快捷的管理调用计算机各部分硬件。Thus a computer-divided into three layers, the application "-" operating system "-" hardware systems, particularly as shown in FIG. Applications are run on the operating system and the operating system is running on computer hardware, operating system, and therefore we collectively known as computer hardware platform that applications are developed and run on the platform of the computer .
Common operating system windows system, linux system, mac systems.
Second, programming and programming languages Introduction
1. What is the programming.
Programming refers to programming, a person (programmer) to their logical thinking and intention to tell a computer program written by, so that the computer to complete the assigned task. Programming get is a bunch of files, the ultimate goal is to get the computer to complete the assigned work through this pile of files.
2. Why programming.
Programming allows the computer to understand human thinking logic and intention to complete some specific task, freeing manpower.
3. programming language.
Interpersonal communication requires language, such as Chinese, English, etc., the same man and machine exchanges also need some kind of communication medium, which is the programming language.
Programming language is divided into three languages: machine language, assembly language, high-level language
Machine language
Machine language is the angle standing computer program to develop, and the computer can identify the high and low frequency, so the computer language is a series of 0 and 1 with this binary code written instructions, the advantage of computer instructions written in a standing angle , more easily understood by computers, high efficiency, direct control of the computer hardware. The disadvantage is too complex, the development of low efficiency, rely on specific computer hardware, cross-platform poor.
Assembly language
Assembly language and machine language essence are the same, are operating directly on the hardware, but uses a command identifier abbreviation is easier to recognize and remember. It also requires the programmer to every step of the specific operation command of written form. The advantage is relative to the machine language, English label programming is relatively simple, lower efficiency, higher development efficiency. The disadvantage is still the hardware directly, compared to machine language, the complexity is lower, but still high, so the development efficiency is still low, as dependent on specific hardware, cross-platform poor
High-level language
High-level language is standing human perspective, people say words that use human characters to write programs, and human character is to send commands to the operating system rather than the hardware directly, so high-level language is dealing with the operating system senior herein refers to the high-rise, developers do not need to consider hardware details. The advantage is the development efficiency can be greatly improved, the disadvantage is the high-level language from the hardware far closer to human language, humans can understand, and the computer will need to understand through an interpreter, so the efficiency will be lower than the low-level language.
High-level language compiler can be divided into type (such as C) and interpreted (python)
Compiled
The compiler code into binary instructions all computer can recognize, after the operating system will hold compiled binary instructions directly operate the hardware. The advantage is compiled once and then you can run repeatedly took the result, without the need to be translated again, the efficiency is higher than interpreted drawback is that the code is compiled for a translation of a platform, the current result of the translation platform can not get another platform, That does not work across platforms
Interpreted
Similarly simultaneous translation, the need for an interpreter, the interpreter reads the program code, while the translation side perform, the advantage is the code to run is dependent on the interpreter, different platforms have the corresponding version of the interpreter, so the code is cross-platform operation, drawback is that
each execution needs to be translated, the efficiency is lower than that compiled.
4. Summary
Efficiency: Machine Language> Assembly language> high-level language (compiled> interpreted)
Development Efficiency: machine language <assembly language <high-level language (compiled <interpreted)
Cross-platform: interpreted with a strong cross-platform type