PRT
    by Peter Warren    

    PRT is a simple printer buffer. The command would normally be
    included in the AUTOEXEC.BAT file, but can be used at any time.
    The first time it is used, the buffer is created and made ready for
    use. If PRT is executed at any later time, the buffer is emptied.
    To change the size of the buffer, (maximum=50k bytes), it is
    necessary to re-boot.
             
    EXAMPLES:
             PRT 50          will create a 50k Buffer (first use)
             PRT             will create a 1k Buffer (first use)
             PRT             will empty the buffer (subsequent use)
    
             Any data now sent to the parallel port (LPT1), will go
    very quickly into the buffer, and you can continue work while the
    printer does it job. A 50k buffer will hold 10-20 pages of text,
    but will soon fill up if the dot addressable graphics modes are
    used much!