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ways, and hope that between this and your computer’s BASIC
manual you will be able to stay with us.
First on our list is Microsoft BASIC’s way of communicating
with the printer. They just add an “L” to the beginning of the
LIST and PRINT commands, making them LLIST and LPRINT.
This method is used by more computers than any other and so
we will use it throughout this book, after telling the rest of you
how to follow along.
Microsoft BASIC is used by TRS-80 computers, IBM-PC
computers, many CP/M computers, and many other computers.
(Look in your BASIC manual; it will probably say if it’s Microsoft
BASIC.)
Next we need to talk about Apple II computers. They have a
real simple system. To list a program that you have loaded into
memory, just type:
PR#l
LIST
PR#@
The PR#l says “send everything to the printer,” the LIST sends
it, and the PR#O says “OK, back to the screen now.”
Some other computers require you to open the printer as a
numbered device, and then direct the output to that device. For
example, to list a program on the printer with a Commodore
C-64 computer you type the following:
OPEN4,4
cMD4
LIST
CLOSE4
This says that the printer is device 4, directs the output to it,
lists the program, and finally closes device 4.
The appendix gives more information about listing programs
on various computers. Find the appendix that tells how your
computer works, and try it.
Now that we all know how our computers address the printer,
let’s try listing a BASIC program. Load a BASIC program and
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