FDO stands for Form Definition Operator. AOL communicates using this programming language. For example, after clicking any icon or button in AOL, FDO code is sent by the AOL system and interpreted by your AOL to create a window. So, the FDO language is the language used to describe forms on the AOL client. This site has focus on learning how to program in FDO and provides a surfeit of examples and tutorials for those who want to learn.

The 1988 version of FDO, FDO88, is used in the GEOS version of the AOL client, PCAO, and the Macintosh clients before version AOL version 3.0. FDO91 is the 1991 version and is the language used in the Windows client, the Magic Cap client, and the Macintosh client (versions 3.0 and later).

As of right now all .fdo scripts on this site are for AOL 4.0 and above.

The easiest way to execute an FDO stream is with the Star Tool. As shown on the image to the right, click the "Play Text Stream..." menu item and navigate to the FDO script that you want to run.

Another way to execute FDO streams involves Visual Publisher Designer. The first method is to open the chosen FDO script in a text editor then just copy the script and paste it into a new form with VPD. Some versions of VPD actually have an option to open *.fdo files.

Using AMPs

AMP stands for Area Manager Project. Area Manager is part of the Visual Publisher Suite. AMP files are a collection of FDO forms created using VPD. After installing VPD, all you have to do to open AMPs is go to Area Manager > Open Project.