How computer really works

  • BIOS (or UEFI) received power on signal
  • BIOS initialize all direct peripherals
  • BIOS looks for a bootable device
  • BIOS switch to bootloader
  • Bootloader loads kernel
  • Kernel initialize everything
  • Kernel switch to userland (init, systemd-init, wininit.exe)
  • Init starts service manager (systemd, openrc, svchost.exe)
  • Service manager starts real software (nginx, sshd, kde4)

How computer really works

Process tree

henyxia@yggdrasil:~ pstree
systemd─┬─ModemManager───2*[{ModemManager}]
        ├─NetworkManager───2*[{NetworkManager}]
        ├─alsactl
        ├─auditd───{auditd}
        ├─avahi-daemon───avahi-daemon
        ├─bash───firefox─┬─RDD Process───3*[{RDD Process}]
        │                ├─4*[Web Content───42*[{Web Content}]]
        │                ├─Web Content───39*[{Web Content}]
        │                ├─2*[Web Content───41*[{Web Content}]]
        │                ├─WebExtensions───32*[{WebExtensions}]
        │                └─80*[{firefox}]
        ├─bash───pavucontrol───3*[{pavucontrol}]
        ├─bash───spotify─┬─spotify───spotify───11*[{spotify}]
        │                ├─2*[spotify───4*[{spotify}]]
        │                └─29*[{spotify}]