Indexed Sun Message Store is a dedicated data store for the delivery, retrieval, and manipulation of Internet email messages. This message store works with the IMAP4 and POP3 servers that ship with SIMS. It saves any message that conforms to RFC 822 specifications, and recognizes the Multipurpose Internet Mail Extensions (MIME) content format.The main advantage of the Sun Message Store is its ability to save only a single copy of any outgoing message that is sent to a distribution list, provided all recipients are on the same mail server. For example, if a message is sent to 20,000 users on the same server, only one master copy of the source message is saved in the store. In terms of space usage, the Sun Message Store is very conservative.