We could talk about the devices and
the nature of the dialogue, what kind of feedback we get
from the computer for each of the discrete character strokes
and actions that the user goes through when he's making
when he's executing a command. So that system's
really represented to a user by a repertoire of commands
he has, by the function of each of those commands, and
by the control dialogue he has for each of them.
So they go all together in making
a design. And to do it well, you have to be very careful
about the nature of the functions in that repertoire and
the nature of the way they're controlled. We have developed
a very special language for talking with extreme precision
about these controls, both the command functions and the
control dialogue for them.