Commodore PET - Mounting the Data Tape; WRITING A DATA FILE

PROGRAMMING GRAPHies
Any graphies sketehed by you direetly onto the sereen will be instantly lost
when you exeeute a NEW statement or turn the power off unless you first eonvert
the graphies into a program.
Vou ean eonvert any design sketehed onto the
sereen into a program simply
by making eaeh line on the sereen a string
whieh
is to be printed as part of a program.
After you have sketehed the square, move the eursor ta the HOME position.
Do not press
CLEAR or RETURN. If you press CLEAR you will lose your pieture
forever. If you press
RETURN, "READY." will be written through the middle of the
square
as shown below:
•
Or, if you had made your square so large that the horizontal lines of the square
were printed on the top and bottom rows of the sereen, and the eursor was posi-
tioned
on the bottom line, a RETURN would cause the display to roll up one line in
order to
write the READY message on the next line. losing the top of the pieture.
Before RETURN
After RETURN
For this reason, pietures larger than 39 eharaeters wide or 24 eharaeters long
should never
be drawn in calculator mode.
Once the cursor
is HOMEd, the next step is to move each line of the picture
to the right in order to insert line numbers, question marks (shorthand for
PRINT)
and quotes. This converts each line from calculator to program mode so it may be
saved on a tape file.
When the cursor has been HOMEd. it should be at the upper left corner of
the square (Figure 5-4a). Key
INSERT five times so that the top line of the square is
shifted five spaees ta the right (Figure 5-4b). Now there is enough room to type a
line number
(100), a 7, and opening string quotes (Figure 5-4c). Then press
RETURN (Figure 5-4& The top line of the square is now a programmed statement.
Continue doing this for each line. incrementing each line number by one hundred
until the entire square has been converted into program statements (Figure 5-4e-
f).
229