Android uses a special inter-process communication system d-bus.
We know that there are many communication mechanisms between processes, such as CORBA, dcop, COM, soap, XML-RPC... too much.
Why is there a D-bus? In other words, what is D-bus? Why use such a unique communication system?
Some of the following documents are from D-bus's FAQ (http://dbus.freedesktop.org/doc/dbus-faq.html ).What is D-bus?
D-bus is a system with an object-oriented interface protocol frame and daemon processes that application users discover and monitor each other. in other words, it is a communication system between processes. It consists of two Daemon Processes and one is the system scope, A set of advanced features such as lifecycle tracking, service activation, and Security Policy Check provided by the user's session scope. The D-bus daemon can start services to provide some functions to other programs.
Is d-bus highly efficient?
D-bus efficiency, D-bus is about 2.5 times slower than the direct use of socket to read and write data. Compared with other communication mechanisms such as CORBA and dcop, D-bus
Both are slower. This efficiency is mainly influenced by its design philosophy: it does not trust the data sent from the peer end and must undergo complex verification.
What is the applicability of D-bus?
D-bus is not a common communication system, which is obviously different from that of CORBA.
It is specific. D-bus is designed to serve as the separation and communication between user interaction interfaces and system services (daemon processes) and between system services (daemon processes. At the beginning of the D-bus design, we did not consider cluster, P2P, and communication between distributed applications. As to whether it is suitable for the above complex applications, let's try it by yourself. D-bus is not used to replace soap, XML-RPC, please use these places.
What is the difference between D-bus and other inter-process (distributed) communication middleware?
D-bus can be seen as the next generation of dcop, which is more complex than dcop, and dcop is used as an opensource desktop application.
Communication. However, the efficiency of D-bus is slower than that of dcop, because more data checksum and more layers are implemented.
D-bus and ice (Inter-client exchange http://www.x.org/X11R6.8.1/docs/ICE/ice.pdf), xsmp, ice is developed for xsmp, dcop and xsmp are built on ice, in principle, both xsmp and dcop can be replaced by D-bus.
D-bus and zeroc ice (Internet communications engine). Ice is something at the CORBA/soap level and is more powerful than D-bus. Ice is a dual-license.
D-bus and DCOM. DCOM is an IPC System in windows. Similar to CORBA, DCE. D-bus is apple, and DCOM is orange ?!
D-bus and soap, D-bus are persistent connections, and soap is generally carried over a connection between a request and a response in HTTP. It can be a connection at a time, soap is built on XML, and D-bus is not.
Many implementations of D-bus and CORBA, such as orbit, are faster than D-bus (libbus, an important design concept of D-bus is that it does not trust the data sent from the peer,
Complex verification is required. both CORBA and D-bus use two-mechanism communication protocols, but CORBA is more common and open. Many areas of D-bus are hard-coded, so d-bus must be simple.
More.
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It is obvious that D-bus makes concessions on efficiency for security considerations and gives priority to structural design. This is obviously different from other communication middleware systems.
Android must use a communication system that is not given priority in efficiency. It has clearly revealed the Security preferences of Android designers. That is to say, the security priority is higher in the design policy.
Android coupling the user interface and service through D-bus. This Division Policy is a typical separation permission design method in software system security design. Is it accidental? This is the only one? |
