250
The
VIC
20
User
Guide
FILES
Computer
data
are stored infiles. This allows you to locate information
you have placed in a certain category.
To
look up a word beginning with
"C"
in the dictionary, you would
turn
to the section with the heading
"C."
Similarly,
to
find information
on
a cassette
or
diskette, you would instruct
the computer to locate a section (file) with a heading (file name) you
assigned.
VIC
data
files
can
have names
that
are much longer
than
the single-
letter headings in the dictionary: File names can be
up
to
16
characters long.
The length
of
the files
is
limited only by the space available on the diskette
or
cassette tape. The number
of
files on a 1540 diskette
is
limited to
144.
There are two kinds
of
files: program files
and
data
files.
Program
Files
Whenever you have a program in the computer memory
that
you wish
to save in order to use it again, you may SAVE it
on
tape
or
diskette.
To
read
it back into the computer, you
LOAD
it into memory. You should give each
program a unique name so the computer can differentiate one from the
other. When you are using the Datassette
to
store programs, you
don't
have
to
use file names, since the computer can simply be instructed to
LOAD
the
first program it encounters. This
is
not true
of
the disk drive. You must tell
the computer which file you want when you load
or
save on a disk.
To
use a program file, you load and
run
it,just as if you had entered the
program by hand. The advantage
is
that
you do
not
need to enter the
program by hand.
In
general, the size
of
a program you store
on
disk
or
tape
will be limited to the
amount
of
memory available in your computer. This
is
because a program
is
normally saved in its entirety. You cannot easily save
part
of
a program and then save the rest
of
the program later.
One way to handle programs that will not fit into your computer's
available memory space
is
to break them into shorter programs and simply
load each section
of
the program separately and run it.
In
this fashion, you
can execute programs
that
are much larger
than
the memory space in your
VIC.
If
you decide to do this, make sure
that
the first program section that
you load
is
longer than any
of
the sections it calls. This
is
necessary because
the program variables will be stored
at
the end
of
your program's first
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