Abstract: Checking the availability of a rental resource by providing a commitment memory area configured to store at least one resource data element corresponding to a rental resource, the at least one resource data element configured to store at least one commitment period made up of at least a start time and an end time, receiving a commitment request including a first start time and a first end time, and returning a positive availability response when the first start time and the first end time are not stored in any of the at least one commitment periods in any of the at least one resource data elements. In further embodiments, a positive availability response is returned when the time period defined by the first start time and the first end time does not intersect with at least one commitment period in each of the resource data elements in the commitment memory area.