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Putting Gemini
to
Work
There it is, a reference sheet that summarizes the various type
styles that Gemini can produce. If your printout looks like Figure
5-2, great! Turn your printer "off;' advance the paper, and tear off
the tables. We will now analyze the program and printout to learn
how we managed to do what we did.
On the Other Hand . ..
If you made a typing error that caused the program to "belly flop;'
or if your printout looks strangely dissimilar to Figure 5-2, you
should reset Gemini and try again. The printer may have received
an unwanted function code. Or, perhaps the communication
became garbled between your computer and Gemini. Whatever
the problem, reset (initialize) Gemini and try again.
ANALYZING THE PROGRAM
In this section, we'll analyze the program you entered, using Figure
5-1 as your reference. Before we start, you might want to SAVE the
program on disk or tape to avoid having to retype it if you ever want
to use it again.
Let's begin by considering line 10, shown in Figure 5-1. This
line tells the BASIC interpreter that the printer will accept 132
characters per line. This prevents BASIC from tossing in extra
carriage returns and line feeds where we don't want them.
Lines 20 through 70 are used to set some printer controls to
more easily remembered codes. The escape code (which is ASCII
decimal code 27) is set to ESC$. The command that tells the printer
to advance one line (ASCII code 10) is set to LF$. The variable FF$
is set to ASCII code 12, a command to Gemini that the printer
should advance to the top of the next page. The default value, set
by power "on" or receipt of the software reset, is 66 lines per page.
Line 30 sets the printer command to change type size. The
format of this command is ESC$
+
"B"
+
n, where n can be 1,
2, or 3. If n is 1, the type size is 10 characters per inch (CPI). Th is
is the type size of a standard typewriter's print, called "pica:' Pica
is the type size you select when Gemini is initialized, until and
unless you ask for different type size. If n is 2, the type size is 12
CPI, the same size as "el ite" typewriter print. If n is 3, the type size
is 17 CPI, the size of the compressed type we used for the listing
in Figure 5-1.
65
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