Application programs may use datasets auxiliary to the input and output datasets. Auxiliary data is controlled by definitions analogous to "in", and "out". The Dictionary for auxiliary data may be defined by alias names like "vel", "Vp", "Vs", "geom", or "norm". An application may allow the end user to override the format and data names. For example,

vel=Angola_vel
vel_data=HAngola_vel_@
vel_format=fcube
    

may be accepted. Auxiliary Dictionaries and data typically do not use "stdin:" and "stdout:" for defaults. However, nothing prevents the user from using "stdin:" or "stdout:".

vel=stdin: