IRCd

The IRCd accepts connections from IRC clients and other IRC servers and builds where appropriate, links to other IRC servers around with these to form an IRC network. Main task is to receive chats and so to convey the individual messages between IRC clients, the interlocutors.

The first IRCd was developed as free software in 1988 by Jarkko Oikarinen. Most IRC networks use other IRC daemons that are either enhancements of the original or other IRCDs, or have also been developed completely from scratch, as InspIRCd. The version of a IRCDs used on a server can usually query the IRC command / version.

IRC services can be seen as an extension of the IRCd that offer more features for users, and are external programs that connect to the IRCd as well as the clients or other servers on the network.

IRC daemons are usually a single system process without threads, since most actions on the global status of the user or channel in the memory read and often also need write access, and threads would hardly allow speed increase.

This places special demands on the design of software: In order to enable real-time chat, the process at no time may longer block at a specific location or waiting for external actions. For this reason, for example, DNS queries are often carried out by an internal resolver instead of the operating system functions, such as what also allows multiple simultaneous name resolutions.