Input devices are also stored on the system database, using DFSETUP. Input device definition allows you to specify multiple input devices owned by a given device type. This means that more than one input device may be active at any one time in an application.
A typical input situation is one where a till has both a keyboard and a scanner attached. The cashier is free to use either device for input of a product code, or both.
You can find more information on input devices in Input Devices of a Device Group.
Commonly, in a system using an OSDI, the user will be running using a non-standard keyboard. As a result you are likely to want to modify the standard userdata.sys keyboard settings, either to generate a special userdata.sys which a developer running on a normal PC without the special keyboard can use to test the application, or to create a suerdata.sys to be used on the live system. You can find more information in Keyboard Customisation.