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DSKF
To return the free area remaining on the disk.
DSKF (<drive name>)
PRINT DSKF ("A:")
DSKF returns the amount of free area in the disk set in the
specified disk drive in units of kilobytes.
<drive name> is a string with a value of "A:" through "D:".
If the RESET statement is not executed after the disk is
replaced, DSKF will not return a correct value, so caution is
advised.
Also, as the memory area for BASIC DOS is allocated in
2K-byte units, called blocks, the value returned by DSKF will
change in multiples of two.
To read data directly from the disk
DSKI$ (<drive name>, <track No.>, <sector No.>)
A$=DSKI$ ("A:", 1, 3)
DSKI$ reads one logical sector from the specified drive and
track and returns the result as a 128-byte string.
The specification of <drive name>, <track No.> and
<sector No> is the same as DSK0$ and, as with DSK0$,
there is no need for opening or closing.
(See DSK0$.)
To return the end-of-file code.
EOF (<file number>)
IF EOF (1) THEN CLOSE #1 ELSE GOTO 100
The file specified by <file number> must have been opened
for the input mode. EOF checks if the file specified by <file
number> has reached its end.
EOF returns -1 (true) if the end of the file has been reached
and returns 0 (false) if not.
If the specified file is RS-232C port ("COM0:"), EOF returns
-1 when the buffer is empty and returns 0 when the buffer
is not empty. The EOF function always returns 0 (false) for
the file assigned to the keyboard.
INPUT$
To return a string of characters read from a specified file.
INPUTS (<number of characters> [,[#]<file number>|)
A$=INPUT$ (5, #3)
INPUT$ reads a string of characters in the number specified
by <number of characters> from the file specified by <fite
number>. If <file number> is omitted, characters can be
input from the keyboard; but the characters input from the
keyboard are not displayed on the screen, unlike the
execution of an INPUT statement.
INPUT$ is in a wait state until a string of characters specified
by <number of characters> is all input. However, if any input
data exists in the input buffer, INPUT$ reads characters from
the buffer.
With an INPUT$, all characters except BREAK key are read
as is. Therefore, INPUT$ allows the input of characters, such
as Carriage Return (character code 13), etc., which cannot be
entered by INPUT and LINE INPUT statements.
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