Information Presentation Facility (IPF) is a system for presenting online help and hypertext on IBM OS/2 systems. IPF also refers to the markup language that is used to create IPF content. The IPF language has its origins in BookMaster and Generalized Markup Language developed by IBM. The IPF language is very similar to the well-known HTML language, version 3.0, with a range of additional possibilities. Therefore, a trained user may use virtually any word processor when creating IPF documents. The IPF language consists of 45 basic commands.
IPF files are compiled using the IPF Compiler (IPFC) into viewable INF or HLP files. IPF HLP files are distinct from the WinHelp HLP files that are prevalent in Windows.
OS/2 contains a built in viewer, and there are other viewers available for other platforms.
Here is a sample of IPF markup from IBM's Information Presentation Facility Programming Guide.
IPF is still used as part of OS/2's latest incarnation, eComStation. It is otherwise rarely used, although there are several tools that can read or write IPF files.