Commodore Plus 4 - Page 344

332 Using Peripheral Devices
where filenumber is the logical file number to be associated with the command
channel and device is the device number of the disk. As usual, when communica
tion through the command channel is complete it must be closed as follows:
CLOSE filenumber
where filenumber is the same logical file number used to open the channel.
Examining the Directory of a Diskette
The directory of a diskette lists all the files stored on the diskette and the number
of sectors each file occupies. The directory cannot list individual sectors allocated
with direct-access commands, but the blocks free total does reflect those alloca
tions. The BASIC 3.5 command is
DIRECTORY DdrivePunitfflename
where drive is the optional drive number (which is not needed for the 1541), unit is
the optional device number of the disk drive, and filename is an optional file name
to search for. The filename is a literal string (in quotes) or a string expression (in
parentheses). Wild cards may be used to get a directory of all those files with
similar names.
Another way of examining the directory is to type
LOAD" $",device
where device is the device number of the disk drive, and then
LIST
Note: The LOAD command erases the program in BASIC memory.
Formatting a Diskette
Before a diskette can be used for storing information, it must be formatted.
Formatting creates data areas on the diskette that the disk drive can recognize.
Formatting a diskette previously used to store information erases all the informa
tion on the diskette. To format a new diskette, the HEADER command can be
used. Its syntax is
HEADER diskname ^identification,!^ drive,ON Uunifc