The Pocket APL Runtime Engine is a dynamic link library (DLL) that is required to run applications which have been written using Pocket APL, an immensely powerful rapid application development system for the Pocket PC.

The Pocket APL Runtime Engine is included with the Pocket APL development system, but must be purchased separately to run a stand-alone Pocket APL application.

The Pocket APL Runtime Engine can host any number of different Pocket APL applications.

If you already have the full development version of Pocket APL,  it is not necessary to purchase the Pocket APL Runtime Engine to run a separate Pocket APL application because you already have it.

If you purchase several different Pocket APL applications for a PDA, you need just one Pocket APL Runtime Engine licence  and download for that PDA.