Defining your terminal allows you to use the forms-based utilities and the many features of Ingres. Your computer system can support a wide variety of terminals, each with its own particular characteristics.

The termcap file contains a description of all terminals supported by Ingres, including their color capabilities and available function, control, and arrow keys. Each supported terminal has a termcap description that is based on the vendor's specifications for that device. This appendix lists supported terminals. For unsupported terminals, you must write your own termcap descriptions. For more information, see the appendix "Writing Termcap Descriptions."

When you start the Forms Run‑time System, it uses the TERM_INGRES environment variable/logical to determine the user's terminal type and verifies basic terminal attributes. The terminal type defined by TERM_INGRES tells the Forms Run‑time System, which terminal description to read from the Ingres termcap file. The type is checked only once for each session, so the user must exit the current session to reset TERM_INGRES to change terminal types.

Forms Run‑time System key definitions can be changed dynamically by the installation, terminal type, user, and application key mapping files. For more information on key mapping, see the appendix "Defining Function and Control Keys."