A card index system that is constantly updated to reflect occupied and vacant rooms. In the evening, the room rack contains forms for only those registered guests remaining for the night who are to be charged for rooms. A daily room report can be prepared from the room rack. Also, see Whitney System.

Room Rack —  An array of metal file pockets designed to hold room rack slips arranged by room number. The room rack summarizes the current status of all rooms in the hotel.