Advanced Function Printing (AFP) is a document format originally defined by IBM to drive its printers and support the typical form printing on laser printers.
The original tool to produce this format and to drive the IBM printers was the so called PSF (Print Service Facility), which is still until today found in IBM mainframes. It is driven by the input data to be printed as well as the definitions on how to place the data on the page, the so called PAGEDEF and FORMDEF. This service also allowed to have electronic forms to print on, named OVERLAYS.
PSF is not only able to format the documents, but also to drive AFP or, more precisely, IPDS printers. IPDS stands for Intelligent Print Data Stream. It is a bidirectional format where the software is constantly in control of the printer and knows at all times the status of the pages sent to the printer, making it convenient for high volume production printers, that print 100 pages or more within a minute.
IBM also offered the PSF software to drive the IPDS printers using the AFP format not only on the mainframe, but on all of the their platforms, so there were PSF/390 (for the OS/390 mainframe), PSF/6000 (for the RS/6000 AIX9), PSF/400 (for the AS/400) and PSF/2 running under OS/2. Unfortunately, all of these behaved slightly differently, and IBM renamed PSF then into InfoPrint Manager.
Included with the PSF tools is ACIF (AFP Conversion and Indexing Facility) that allows to produce the AFP documents as a file in order to keep them and print them later, as well as adding and index to the document, very similar to Bookmarks in PDF, used for archiving purposes.
AFP originates in the mid 1980s, when storage space was still an expensive commodity, so it was designed to be very small, which is why still today it is a very popular format to manage high volumes of documents, such as in banking, telecommunication and insurance companies. The format originates from the MVS environment, so it typically uses the EBCDIC based codepages. As with all page description languages (like PostScript, PDF, and PCL), it is necessary to use a viewer in order to display the pages.
One of the more notable features of AFP printers is that output data can be placed at any addressable point on a page. This capability is called all points addressability (APA). APA gives AFP prints the freedom to create output anywhere on a page, as opposed to being limited to just line and character positions.
==ExternaInformation on AFP.