Why do they call it a Daemon?
The term daemon has an interesting history in computing — and it’s directly related to why Cloudflare calls their tunnel client cloudflared a daemon.
The term daemon has an interesting history in computing — and it’s directly related to why Cloudflare calls their tunnel client cloudflared a daemon.
1. Origin of the Word "Daemon"
- The word daemon comes from Greek mythology:
A δαίμων (daímōn) was a guiding spirit or lesser deity that worked in the background, influencing the world without being seen. - Early computer scientists at MIT in the 1960s (Project MAC, Multics system) borrowed the term.
They wanted a word to describe programs that ran invisibly in the background, automatically doing useful work without user intervention.
2. In Computing
- A daemon is a background process that runs continuously and performs tasks like:
- Listening for network requests (e.g., httpd for web servers).
- Handling scheduled tasks (e.g., cron).
- Managing system services.
- Unlike normal programs, daemons:
- Usually start at boot time.
- Run in the background without direct user interaction.
- Provide services to other software or users.
3. Naming Conventions
- In UNIX/Linux tradition, daemon names often end in “d”:
- sshd → Secure Shell Daemon.
- httpd → Apache Web Server Daemon.
- mysqld → MySQL Database Daemon.
- cloudflared → Cloudflare Tunnel Daemon.
- That “d” at the end is the telltale marker: it’s not the program itself, but the background service version of it.
