很长一段时间以来，我一直很想知道调用守护进程程序或线程"守护进程"的历史原因。

Lat: daemon, latin version of the Greek"δα?μων" ("godlike power, fate, god")

• god,
• a subordinate deity, as the genius of a place or a person's attendant spirit

有许多问题可以解释守护程序是什么以及它们的行为，但是没有一个问题可以解释"守护程序"这个术语的起源，该术语用于在后台运行的程序，如sshd。

为什么我们要将后台运行的程序命名为守护进程？

查看维基

According to Fernando J. Corbato who worked on Project MAC in 1963 his
team is the first to use the term daemon. The use of the term daemon
was inspired by Maxwell's daemon, in physics and thermodynamics as an
imaginary agent which helped to sort molecules.

"We fancifully began to use the word daemon to describe background
processes which worked tirelessly to perform system chores."

In the Unix System Administration Handbook, Evi Nemeth states the
following about daemons:

"Many people equate the word"daemon" with the word"demon", implying
some kind of satanic connection between UNIX and the underworld. This
is an egregious misunderstanding."Daemon" is actually a much older
form of"demon"; daemons have no particular bias towards good or evil,
but rather serve to help define a person's character or personality.
The ancient Greeks' concept of a"personal daemon" was similar to the
modern concept of a"guardian angel"—eudaemonia is the state of being
helped or protected by a kindly spirit. As a rule, UNIX systems seem
to be infested with both daemons and demons."

根据维基百科：

这个术语是由麻省理工学院的Mac项目的程序员创造的。他们取了麦克斯韦魔王的名字，一个来自思想实验的假想生物，它不断地在背景中工作，对分子进行分类。

Unix系统继承了这个术语。麦克斯韦的恶魔与希腊神话中对一个恶魔的解释是一致的，它是一个在幕后工作的超自然生物，对善与恶没有特别的偏见。然而，BSD和它的一些衍生产品已经采用了一个基督教恶魔作为他们的吉祥物，而不是希腊恶魔。

这里更多。

在这里。

在这里。