A range of devices can be accessed in DP4 using a facility called device integration. The DP4 Operating System Device Interface package can be used to define drivers for special devices. For example, a device driver may be needed for an input device such as a scanner or a magnetic stripe reader, and an output device such as a receipt printer or an operator display. In each case, your application need not know the characteristics of the device.
Devices in DP4 are maintained separately from an application, and are accessed by their device names. If the parameters of a device change, the changes need only be made to the definition on the DP4 System Database