Operating system (OS)

1. Operating System (OS)

Schematic diagram of the operating system as an interface

A computer without an operating system is usually called bare metal

• If you want to run your own program on bare metal, just The program must be written in machine language
• If the operating system is installed on the computer, you can install the supported high-level language environment on the operating system, and use the high-level language to develop programs

1.1 The role of the operating system

• The most basic and important system software in modern computer systems
• Yes The first layer of software configured on computer hardware is the first expansion of the hardware system
• The main function is to manage hardware devices, and Provide a simple interface for users and applications for easy use
• Others, such as compilers, database management systems, and a large number of application software, are directly dependent on the support of the operating system

1.2 Mainstream operating systems in different application fields

• Desktop operating system
• Server operating system
• Embedded operating system
• Mobile device operating system

1> Desktop operating system

• Windows series
  • Large user base
• macOS
  • Suitable for developers
• Linux < ul>
• Less application software

2> Server operating system

• Linux
  • Safe, stable and free
  • High market share

< li>Windows Server

• Paid
• Low share?

3> Embedded Operating system

• Linux

4> Mobile device operating system

• iOS
• Android (based on Linux)

1.3 virtual machine

Virtual Machine refers to software A simulated complete computer system with complete hardware system functions and running in a completely isolated environment

• The virtual system generates a new virtual image of the existing operating system, which is exactly the same as the real operating system Function
• After entering the virtual system, all operations are carried out in this new independent virtual system. You can install and run software independently, save data, and have your own independent desktop, which will not affect the real system. Any impact
• A type of operating system that can flexibly switch between the existing system and the virtual image