BASIC PROGRAMMING LANGUAGE
The BASIC programming language is a special language that lets
you communicate with your Commodore 128. Using BASIC is
one means by which you instruct your computer what to do.
BASIC has its own vocabulary (made up of commands,
statements and functions) and its own rules of structure (called
syntax). You can use the BASIC vocabulary and syntax to create
a set of instructions called a program, which your computer can
then perform or “run.”
Using BASIC, you can communicate with your Commodore 128
in two ways: within a program, or directly (outside a program).
Direct Mode
Your Commodore 128 is ready to accept BASIC commands in
direct mode as soon as you turn on the computer, ln the direct
mode, you type commands on the keyboard and enter them into
the computer by pressing the RETURN key. The computer
executes all direct mode commands immediately after you press
the RETURN key. Most BASIC commands in your Commodore
128 can be used in direct mode as well as in a program.
Program Mode
ln program mode you enter a set of instructions that perform a
specific task. Each instruction is contained in a sequential
program line. A statement in a program may be as long as 160
characters; this is equivalent to four full screen lines in 40-
column format, and two full screen lines in 80-column format.
Once you have typed a program, you can use it immediately by
typing the RUN command and pressing the RETURN key. You
can also store the program on disk or tape by using the DSAVE
(or SAVE) command. Then you can recall it from the disk or tape
by using the DLOAD (or LOAD) command. This command copies
the program from the disk or tape and places that program in the
Commodore 128’s memory. You can then use or “execute” the
program again by entering the RUN command. All these
commands are explained later in this section. Most of the time
you will be using your computer with programs, including
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