Direct Mode; Program Mode - Commodore 128D User Manual

n
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 instruc
tions 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. In 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
In program mode you enter a set of instructions that perform a spe
cific 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 typ
ing the RUN command and pressing the RETURN key. You can also
store the program on disk or tape by using the DSAVE (or SAVE) com
mand. Then you can recall it from the disk or tape by using the
DLOAD (or LOAD) command. This command copies the program
f rohn 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 programs you yourself write, and commercially
available software packages. The only time you operate in direct
mode is when you are manipulating or editing your programs with
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USING C128 MODE—Getting Started in BASIC