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System Specification for C65Fred BowenMarch 1, 1991

GRAPHIC - select graphic mode

    GRAPHIC command#, [,args]

Basically this is a modified C64-type SYS command, minus the address. In the C64DX system, this will represent the ML interface, not the BASIC 10.0 interface which is implemented in the development system.


GRAPHIC CLR initializes (warm-starts) the BASIC graphic system. It clears any existing graphic,modes, screens~ etc. and allows a program to.commence graphic operations from scratch.

HEADER - Format a diskette

    HEADER "diskname" [,Iid] [,Ddrive] [<ON|,>Udevice]

The HEADER command prepares a new diskette for use, sometimes called FORMATing a diskette. There are two types of "newing" a diskette- a long form and a quick (or short) form. You must use the long form when preparing a new diskette for its first use. Thereafter you can use the quick form.

WARNING: Formatting a diskette (long or short) will destroy all existing data on the diskette! In direct mode, you are asked to confirm what you are doing with 'ARE YOU SURE?'. Type 'Y' and press return to proceed, or TYPE ANY OTHER CHARACTER AND PRESS RETURN TO CANCEL the command. In program mode there is no confirmation prompt.

The long HEADER form requires a diskname and an ID. The diskette will be completely (re)sectored, zeros written to all blocks, and a new system track (directory, BAM, etc.) will be created.

        HEADER "newdisk",I01                prepares a new diskette

The short HEADER form is performed when the ID option is omitted. The diskette is assumed to have been previously formatted, and only a new system track (directory, BAM, etc.) is installed. This is roughly equivalent to deleteing all the files, but much quicker.

        HEADER "makelikenew"                re-news an working diskette

The diskname is limited to 16 characters and the ID string to two characters. The same rules apply for the diskname as for a filename. Some Disk Systems use the ID string to tell if you have swapped a diskette in a drive, so it's recommended that the ID string be unique for each of your diskettes. Some more examples:

        HEADER "QUICK"
        HEADER "MYDISK", 123
        HEADER "RECS", I"FB", U9
        HEADER (FILE$), I(ID$), U(UNIT)

HELP - Show the BASIC line that cause the last error

The HELP command is used after an error has been reported in a program. When HELP is typed, the line where the error occurred listed, with the portion containing the error highlighted. Print ERR$(ER) for the error message, and print EN or EL for the error number and error line, respectively. HELP can be used in direct mode or in program mode. Note that, in the case of many I/O errors, there is no associated BASIC error. Check ST or DS$ errors in these cases.

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Read the small print. Last updated August 11, 2003.