If you want to use the microdrive, you'll need cartridge files.  The
    emulator can create an empty cartridge file for you.  You have to
    format it before you can use it.  Type

        FORMAT "m";1;"name"

    to format the cartridge currently in Microdrive 1 giving it the name
    'name'.  Next, type CAT 1 to get a catalogue of the files on it (none
    of course) and the number of kilobytes free.  You can save a file by
    typing for instance

        SAVE *"m";1;"screen"SCREEN$

    Instead of SCREEN$ you can use all other expressions that are permitted
    also when saving to tape, like LINE nnnn or CODE x,y etcetera.  To load
    a file back from cartridge, you type (you guessed it)

        LOAD *"m";1;"screen"SCREEN$

    If the file doesn't exist or is of the wrong type you'll get the
    appropriate error message.  To erase a file, type for instance

        ERASE "m";1;"screen"

    Note that no * is needed (or even permitted), and that only the name
    should be given.  There's another way to create a file on a cartridge,
    and that is by using a command like OPEN #3;"m";1;"name", and printing
    to that stream.  You can use MOVE to move data from stream to stream,
    but I'll not go into that --- it's not very much used anyway.

    Instead of to the microdrive, you can also 'save to the RS232 link'.
    For instance, type SAVE *"b"SCREEN$ (note: there's no name!) to save a
    screen.  On the emulator you can send the output to the RS232 channel
    to a printer (then SAVE *"b" is useless), to a file (can be useful) or
    to the COM port (very useful if you connect a real Spectrum to the PC's
    COM port!).  You can load the data back by typing LOAD *"b"SCREEN$ and
    making sure the RS232 channel is fed with the right input (from a COM
    port or a file).  See also section 2.13.

    If you want to use the RS232 channel for printing, open stream 3 for
    output to that channel by typing

        OPEN #3,"b"

    or

        OPEN #3,"t"

    The first will simply copy everything you send to stream 3 (using for
    instance LPRINT or LLIST) to the RS232 channel; the second converts
    CR's into CR/LF's, breaks off lines at 80 characters and translates
    keywords into character sequences.  "t" is useful for LLISTings, but
    not for anything else.

    Useful extra commands: CLS #, to clear the screen and reset the
    attributes to their reset defaults, and CLEAR # to do a CLS # and close
    all currently open streams (discarding all data that may still be
    buffered!)

    The Interface I uses its own system variables.  At the first error
    message you make (or RASP, or flashing question mark) and at the first
    Interface I statement you execute, it inserts them automatically.  Some
    programs will not run when the Interface I has inserted its system
    variables.  So if you load a game from tape, reset the Spectrum first
    and don't make an error typing LOAD "".  With a bit of exercise you
    should be able to do this.