lastlog is an old ircII terminus standing for log of last messages.
It was coined by BigCheese, original author of ircII.
psyced implements this concept on the server side rather than on the client side. It is used to keep messages stored for you, and generally to let you have your last session's backlog back when you log in.
Every UNI has one such lastlog, which in the case of a place is then called history. It is implemented in the file http://www.psyced.org/dist/world/net/lastlog.c
You can export the chat history of a room into a web page. See http://www.psyced.org/jscript-export for that.
You can tune the size of the log for each person. That's described on the psyced tuning page.
On a PSYC protocol level, the arguments to the _request_do_show_log requests are:
- _match: a substring contained in the log
- _amount: the number of messages to roll back
- _parameter: you don't know what the user typed - could be a match or an amount or something new we don't yet know about.
See also the command descriptions of /lastlog and /history in the manual.