Development environment (DEV): server program development environment is designed to ape their development, configuration can be more casual, in order to facilitate development and debugging, usually open all error reporting.
Test Environment (UAT): General cloning is a production configuration environment, a program in a test environment is not working properly, you certainly can not publish it on production machines.
Production (PROD): refers to the formal provision of external services, usually turn off error reporting, open the error log. It can be understood as environment includes all the features of any project environment used this as the basis, and then do the adjustment or modified according to the individual needs of customers.
Three environment can also be said that the system developed in three phases: development -> test -> on line, in which production is often said that the real environment.
UAT environment: UAT, (User Acceptance Test), user acceptance testing that is acceptance testing, UAT environment it is mainly used as a customer experience environment.
Simulation environment: As the name suggests is the real environment and use the same environment (that is, where the environment has been sold to a customer's system, has become a commercial environment), all configuration, the page display and so should businesses are using the same, the only difference in the environment of performance.