This OS/2 DLL's entry point description is inspired by http://home.clara.net/orac/os2dll.htm, http://www.edm2.com/index.php/Category:Files

These DLL's contain core OS/2 API, exported by kernel (called CP API or Control Program API), and others are mostly “forwarders” to doscalls. We must note here, that in Intel OS/2 doscalls is a virtual DLL. It does not exist on disk. But here exist DOSCALL1.DLL, which is a collections of call gates into the kernel, or implementations of some API's fully in ring3, based on the real kernel API. DOSCALLS is a virtual DLL, which is a pure kernel API merged with doscall1.dll. The kernel will load also the DLL called DOSCALL2.DLL, which is “user defined API's”. This was intended for OEM API extensions. DOSCALLS in modern OS/2 contains implementation of all (or most) Control Program API. Many other DLLs just forwarders to DOSCALLS. We also uses such logic. Only difference is DOSCALLS not lowest library. DOSCALLS also divided onto two libs. DOSCALLS itself, which contains kernel independed parts, and KAL library, which contains kernel depended part. For osFree project KAL just forward all calls to OS/2 Personality server and recieves answer from it with call result. Such approach allow to port CPI to other kernel easely, because kernel-depended part cleary divided into separate layer.