The original VGA Planets has a maximum limit of 500 ships in play at one time. Once this limit is reached, new build orders at starbases cannot be fulfilled until an existing ship is destroyed, recycled, or otherwise removed from the game, thus freeing up a ship slot. When a free ship slot becomes available, there are usually many starbases with pending build orders. A decision must be made as to which starbase will be allowed to build its ship and fill the free ship slot. This is one of the most vexing problems in the game and has been the cause of much debate.
(4.0) PHost 4 (as well as HOST999) allows up to 999 ships in the game. This delays the ship limit, but does not avoid it.
The list of pending ship builds is called build queue. PHost offers three strategies of managing the build queue. These strategies and their parameter are discussed here.
