A Few Words About Poke - Commodore VIC-20 User Manual

A FEW WORDS <
ABOUT POKE j
The command POKE lets you deal with your VIC on a
completely new level. POKE allows you to find a particular
memory location and change what is stored there. Since this
command operates directly on the VIC'S memory, it is possible
to make mistakes by POKEing values into the wrong locations,
or wrong values into the right locations! We want to repeat
what we told you way back in Chapter One: There is no way
you can hurt the computer by typing on the keyboard...not even
with POKE. But you can cause the VIC to just go away
someplace and sulk, cutting you off from any contact. For
example, if you're ready to end this session anyway, try typing:
POKE 788, 0
You may find that the only way you can regain communication
with a computer that has been "insulted" in this way is to type
RUN/STOP and RESTORE. If the "crash" is serious, you may
have to turn it off and turn it on again. This doesn't harm the
computer, but it does mean that whatever program you were
working on will be lost. Even if this should happen to you, a
little typing time is normally the extent of the loss. But it does
suggest that you should be careful of what you POKE, it also
underlines the value of accessories like disk drives and data
cassettes, which can store programs, as well as printers, which
can at least give you a program listing that would help you
reconstruct a lost program.
We recommend that you make a brief study of POKE in
Appendix C before you begin to POKE around indiscriminately
in your VIC. At least try the examples we give you in this book.
Be careful typing those long numbers, and double check your
work before you run your programs. A computer that has been
POKEd in the wrong place may well reason that turnabout is
fair play, and simply "turn you off."
In this chapter, you've learned how to make Bach and
Beethoven sit up and take notice. You know how to drive your
friends crazy and make them long for the good old days when
your VIC was a quiet, mild-mannered little creature that kept
pretty much to itself. So what if the VIC isn't quite as talented
as Beverly Sills or a Steinway concert grand? You and VIC can
still make beautiful music together! Maestro, please...
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