I feel I need to emphasize that your tiers can be many more than the typical three you will have seen drawn in many of the illustrations in this chapter. It is a point often missed by newcomers to distributed, tiered architectures: a tier and a machine are not necessarily synonymous; and the typical user services, business logic, and data services tiering could be increased extensively depending on the needs of the application. Also keep in mind that tiers and physical machines need not be in any one-to-one relationship. However, the machines that distribute components, other than the database server itself, need to have Windows NT (preferably Windows NT Server 4.0) present to run successfully.