Computer programming and programming languages
What is the programming language
Programming language is the medium used to communicate with the computer
What is programming
Programming is a programming language to write files
Why Programming
Let the computer replace human beings, to help humanity work
Composed of five computer
CPU
Controller
Used to control the hardware
Operator
It is divided into logical and arithmetic operations
RAM
Pros: Fast
Disadvantages: small storage, power disappears
External memory
Pros: Large storage, power does not disappear
Cons: Slow
input device
Input information, including a mouse, keyboard, U disk
Output Device
Output information, including a display screen, a printer, U disk
U disk is the IO devices
Mechanical hard drive
Mechanical arm
Read data
Tracks
Storing data
Sector
Division track
The average seek time data
5+4.15=9.15ms
Average seek time
5ms
The average delay time
Computer-7200r / min is 4.15ms
SSD
No average seek time, and based on the propagation speed of light information
Computer operating system
What is the file
The concept of virtual operating system files are provided
What is the application procedure
Applications are a lot of papers
What is the use operating system
The complex instructions to simplify hardware
User / operating system / application / hardware
Hardware: Operating System
Operating System: user / application / hardware
Applications: Operating System
The operating system starts
- Power
- Start a temporary operating system
- Then the temporary operating system to read the address of the operating system path
- Start real operating system
Programming language
Programming language into machine language, assembly language and high-level language
Machine language (low level language)
Interact directly with hardware
Advantages: high efficiency
Disadvantages: low efficiency of development
Assembly language
Interact directly with hardware
Advantage (compared to machine language): the development of high efficiency
Disadvantages (compared to machine language): Low efficiency
High-level language into a compiled language and interpreted languages
Compiled language
Indirect interaction with the hardware
Record, all finished only to be translated documents translated into another obj files in the computer and communication get results
Advantages (compared interpreted languages): High efficiency
Disadvantages (compared to interpreted languages): low development efficiency
For example: C, Java
Interpreted language
He says a translation
Advantage (compared to a compiled language): the development of high efficiency
Disadvantages (compared to a compiled language): Low efficiency
For example: python
Programming Language Category
C: interaction with the hardware
C ++: Object-Oriented C
Java: very good cross-platform
python: omnipotent
PHP: the world's best language
GO: Support high concurrency
js: the worst in the history of the language syntax
Network bottleneck effect
Application networking needs
The network has delayed 10ms, and the efficiency of compiled languages even faster than interpreted languages will 1ms