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Live Keyboard
When a program is running, the keyboard is still active. Commands can be executed,
variables can be inspected and changed, and the state of the computer can be changed.
The term "live keyboard" is used when talking about commands that are executed
during a running program. One of the principal uses for live keyboard commands is the
troubleshooting and debugging of programs in the development stage, as discussed in the
"Debugging Programs" chapter of BASIC Program:mi'ng Tech·niq-ues. See
~~IIltroduction
to the System" for tables showing how to pause, stop and continue a program.
Example of Controlling Program Execution
To demonstrate some of the interaction between a program and the keyboard, enter the
following simple program.
10 DISP "Next
command?"
20
X=O
30 PRINT X;
40 X=X+1
50 WAIT .1
60
GOTO 30
70 END
1. After you have entered the program, execute RUN and observe the CRT. Notice
that the DISP message appears in the display line, the printout area fills with a
sequence of numbers, and the run light indicates that a program is running.
User 1
Caps
Running
"Program-Status" Indicator
1 - - -
(ITF Keyboard Only)
---"Run Light"
Loading and Running Programs
4-9
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