Foreground process group background process group meaning

Terminals with control terminals belong to the frontend, and those with no control terminals or hidden background processes are called background processes.

 

This may be very abstract. The actual example is more specific, such as anti-virus software. If you open his console, you can perform various operations such as hard disk scanning. At this time, he is a front-end process. When you hide his control terminal, it is a background process.

Most foreground processes are used by users.ProgramGenerally (mostly) system processes in the background.

 

 

A Linux background process, also called daemon, is a special process running in the background. It is independent of the control terminal and periodically executes a task or waits to process some events.
Generally used as a system service. You can use crontab to submit, edit, or delete a job.
Daemon means that it is not controlled by the terminal. Most Linux servers are implemented using daemon. For example, the Internet server inetd and the Web Server httpd. At the same time, the daemon completes many system tasks. For example, job planning process crond and printing process LPD. Similar to the daemon ending with "D" on the iPhone, we can see on Mac machines that, after all, they are all UNIX-based kernels.

A foreground process is a process with a control terminal used by the user.

 

Difference 1: You can operate the foreground process, but you cannot operate the background process (except to disable it ).
2. All foreground processes are automatically controlled by the computer, and all background processes are automatically controlled by the computer.

Feature 1: foreground processes can be displayed in the system in the form of windows and dialogs. background processes are unavailable.
2. All processes that are lit in the taskbar can be called the foreground process. The background process is not lit.
3. foreground and background processes can sometimes switch to each other.