The Search Limits dialog controls how long Arasan will search when it is the computer's turn to make a move.
Four different kinds of search limits are available:
Fixed Time per Move: The computer will search for a constant number of seconds when it is the computer's turn to move. If the Fixed Time per Move option is selected, no limit is set on how long you have to move when it is your turn.
Incremental: Each side will have a certain number of minutes to make all moves in the game. But: in addition, each time a move is made, a constant number of seconds is added to the clock for that side. If you set the Increment field to zero, then no time bonus is awarded for making a move, and all moves must be made within the time set in the "Minutes" field.
Tournament: Each side must make a set number of moves within a certain number of minutes. For example, if you set 40 moves in 40 minutes, you can take no longer than 40 minutes to make your first 40 moves. After you have made your 40th move, the clock will reset and you will have another 40 minutes to make the next 40 moves, and so on.
Fixed Depth: The computer will look ahead the specified number of half-moves (one move by one side). The smaller the depth number, the faster the search will complete (a search to depth 1 will take only a fraction of a second). If the Fixed Depth option is selected, no limit is set on how long you have to move when it is your turn.