IBM 5110 User Manual page 9

4
Output
• The display screen, which displays keyboard input and the results of
executed expressions br statements. That is, the display screen is a
means of communication between the system and you.
• The printer, which prints keyboard input (if specified) and the results
of executed expressions or statements. This printed output is
sometimes called hard copy output.
• The tape or diskette on which data can be stored for future
processing.
As mentioned before, a program is a procedure or set of instructions
you establish for doing a job. These instructions are necessary
because a computer cannot think for itself. When defining a program
for the 5110, you can use a programming language called APL. APL is
a simple-to-use programming language with which you describe how
'you want the 5110 to do a job. Also, in APL, a program is called a
user-defined function.
The next chapter presents an approach to analyzing a problem or job
so that an APL user-defined function can be used to help process
information.