Printer symbiont

    This is the mainline interface that handles communication between
the job controller and the device/file dependent modules of the
symbiont. Error handling is also provided in this module. (Also known
as the Symbiont Manager Interface module) 

    Six routines are required in the Device/File Interface module:

	SMB_DFI_INIT - symbiont specific startup procedure
	SMB_DFI_DEVICE_INIT - perform device initialization
	SMB_DFI_PROCESS_FILE - perform file processing/printing
	SMB_DFI_ABORT - perform device specific abort procedures
	SMB_DFI_CLEANUP - perfrom file specific abort procedures
	SMB_DFI_RESUME_TOF - rewind file and resume printing


Imagen Symbiont

    Device/File Interface Module Called by Symbiont Manager Interface
module to read in and conditionally process (impress) files and ship
the text to the Packet Communications module.