DOPEN#l, "readfile" Opens sequential READFILE for reading.

DOPEN#1,' "writefile",W Creates & opens seq WRITEFILE for writing.

DOPEN#l, "file,P',U(u) Opens a PRoGram type file for reading on unit U

DOPEN#l, (rf$),L Open existing relative file whose name's in RF$

DOPEN#a, "rel",L80 Create a relative file with record length of 80

DPAT - Set graphic draw pattern

    DPAT type [, # bytes, bytel, byte2, byte3, byte4]

[*** THIS COMMAND IS SUBJECT TO CHANGE ***]

    type            0-63
    # bytes         1-4
    bytel           0-255
    byte2           0-255
    byte3           0-255
    byte4           0-255

DSAVE - Save a BASIC program into a disk file

    DSAVE "[@]filename" (,Ddrive) [<ON|,>Udevice]

This command copies a BASIC program in the computer's BASIC memory area into a PRoGram-type disk file. If the file already exists, the program is NOT stored and the error message 'FILE EXISTS, is reported. If the filename is preceded with an '@', then if the file exists it will be replaced by the program in memory. Because of some problems with the 'save-with-replace' option on older disk drives, using this option is not recommended if you do not know what disk drive is being used. Use the DVERIFY to compare the program in memory with a program on disk.

To save a binary program, use the BSAVE command.

        DSAVE "myprogram"       Creates the PRG-type file MYPROGRAM
                                on the default system disk and copies
                                the BASIC program in memory into it.
        DSAVE "@myprogram"      Replaces the PRG-type file MYPROGRAM
                                with a new-version of MYPROGRAM. If
                                MYPROGRAM doesn't exist, it's created.
        DSAVE (F$),U9           Saves a program whose name is in F$
                                on disk unit 9.

DVERIFY - Compare a program in memory with one on disk

    DVERIFY "filename" [,Ddrive] [<ON|,>Udevice]

This command is just like a DLOAD, but instead of LOADing the BASIC program file into computer memory the data is read from disk and compared to computer memory. If there's any difference at all a 'VERIFY ERROR' is reported.

Note: if the BASIC program in memory is not located at the same address as the version on disk was SAVEd from, the files will not match even if the program is otherwise identical. The comparison ends when the last byte is read from the disk file.

Use the BVERIFY command to compare memory with binary files.