266
The
VIC
20
User
Guide
I. Turn off all drives except the one you are changing.
2.
Open a command file, such
as
OPEN
l~le,l~
3.
Enter the following command sequence. Note: Don't worry if you
don't understand this sequence; this kind
of
instruction
is
covered in
more detail in the section on advanced disk commands.
PRINTll~,IM-W"CHR.(119)CHR.(0)CHR'(2)CHR'(9+32)CHR'(9+64)
This instruction will change the disk to device number
9.
To
change the disk drive
to
another device number, add that number,
instead
of
9,
to
32
and
64
at
the end
of
the command.
4.
Turn on the next drive and repeat the command sequence above,
using a different device number for each drive added.
Note: Do not turn off any drive
that
has been changed. This will erase
the new device number.
Disk
Data
Flies
Just as there
is
a difference in the way that data files and program files
are handled by the Datassette, there
is
a difference in the way that data files
and program
files
are handled by the disk drive.
There are three different kinds of information that can be stored on the
disk drive. The first, program files, has already been covered. The second
type
is
sequential data files, and the third, random access files.
SEQUENTIAL
FillS
Like sequential
data
files on the Datassette, sequential
data
files on the
1540
Disk Drive must
be
opened before they can
be
accessed. To open a
sequential data file to the disk, use the following format:
OPEN
lin,
dn,
sa,
"drn:file name,SEQ,W"
where:
Ifn
is
the logical file number
dn
is
the device number for the disk drive
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