If your new printer's data stream differs significantly from one of the numerous printer data streams currently handled by the operating system, you must define a new backend formatter. Adding a new formatter does not require the addition of a new backend. Instead, all you typically need are modifications to the formatter commands associated with that printer under the supervision of the existing printer backend. If a new backend is required, see Printer Backend Overview for Programming in AIX 5L Version 5.2 Guide to Printers and Printing.