Message Passing
An RPC is initiated by the client, which sends a request message to a known remote server to execute a specified procedure with supplied parameters. The remote server sends a response to the client, and the application continues its process. While the server is processing the call, the client is blocked (it waits until the server has finished processing before resuming execution), unless the client sends an asynchronous request to the server, such as an XHTTP call. There are many variations and subtleties in various implementations, resulting in a variety of different (incompatible) RPC protocols.
An important difference between remote procedure calls and local calls is that remote calls can fail because of unpredictable network problems. Also, callers generally must deal with such failures without knowing whether the remote procedure was actually invoked. Idempotent procedures (those that have no additional effects if called more than once) are easily handled, but enough difficulties remain that code to call remote procedures is often confined to carefully written low-level subsystems.
Read more about this topic: Remote Procedure Call
Famous quotes containing the words message and/or passing:
“The photographic image ... is a message without a code.”
—Roland Barthes (1915–1980)
“Frequently also some fair-weather finery ripped off a vessel by a storm near the coast was nailed up against an outhouse. I saw fastened to a shed near the lighthouse a long new sign with the words “ANGLO SAXON” on it in large gilt letters, as if it were a useless part which the ship could afford to lose, or which the sailors had discharged at the same time with the pilot. But it interested somewhat as if it had been a part of the Argo, clipped off in passing through the Symplegades.”
—Henry David Thoreau (1817–1862)