An Overview of the Boa Web Server
Boa is a single-tasking HTTP server. Boa does not fork a copy of itself or spawn a thread to handle each incoming connection, but rather internally multiplexes the connections. Boa only forks for CGI programs, automatic directory generation, and automatic file gunzipping, each of which must be a separate process. The primary design goals of Boa are speed and security, in the sense of "can't be subverted by a malicious user", not "fine grained access control and encrypted communications". Boa is not intended as a feature-packed server; if you want one of those, Boa is probably not the right choice.
