D-Bus influenced by DCOP
History and adoption
D-Bus was started in 2002 by Havoc Pennington, Alex Larsson (Red Hat) and Anders Carlsson. The version 1.0—considered API stable—was released in November 2006.
Heavily influenced by the DCOP system used by versions 2 and 3 of KDE, D-Bus has replaced DCOP in the KDE 4 release. An implementation of D-Bus supports most POSIX operating systems, and a port for Windows exists. It is used by Qt 4 and later by GNOME. In GNOME it has gradually replaced most parts of the earlier Bonobo mechanism. It is also used by Xfce.
One of the earlier adopters was the (nowadays deprecated) Hardware Abstraction Layer. HAL used D-Bus to export information about hardware that has been added to or removed from the computer.The usage of D-Bus is steadily expanding beyond the initial scope of desktop environments to cover an increasing amount of system services. For instance, the NetworkManager network daemon, BlueZ bluetooth stack and PulseAudio sound server use D-Bus to provide part or all of their services. systemd uses the D-Bus wire protocol for communication between systemctl and systemd, and is also promoting traditional system daemons to D-Bus services, such as logind. Another heavy user of D-Bus is Polkit, whose policy authority daemon is implemented as a service connected to the system bus.