stateless

Refers to software that does not keep track of configuration settings, transaction information or any other data for the next session. When a program "does not maintain state" (is stateless) or when the infrastructure of a system prevents a program from maintaining state, it cannot take information about the last session into the next, such as settings the user chose or conditions that arose during processing.

The Perfect Example
The most ubiquitous stateless environment is the World Wide Web. The HTTP protocol, which is the communications vehicle for Web transactions, is stateless. After a Web page is delivered to the user, the connection is closed. Counter measures, such as the use of cookies, have been developed to maintain the state of a user moving from page to page on a Web site. Contrast with "stateful," which means that continuity is maintained from session to session. See HTTP and cookie.

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stateless - A stateless server is one which treats each request as an independent transaction, unrelated to any previous request. This simplifies the server design because it does not need to allocate storage to deal with conversations in progress or worry about freeing it if a client dies in mid-transaction. A disadvantage is that it may be necessary to include more information in each request and this extra information will need to be interpreted by the server each time. An example of a stateless server is a World-Wide Web server. These take in requests (URLs) which completely specify the required document and do not require any context or memory of previous requests. Contrast this with a traditional FTP server which conducts an interactive session with the user. A request to the server for a file can assume that the user has been authenticated and that the current directory and transfer mode have been set.