Windows Libraries for OS/2

Microsoft Windows Libraries for OS/2 (shortened to WLO) is an implementation of the Win16 API for OS/2 1.21 and higher, along with an SDK for converting existing Win16 applications to run on OS/2.

History

The first version was 0.9, announced on February 4, 1991 as Microsoft Windows Libraries for OS/2 Development Kit. To make matters confusing, as is common with Microsoft, another "advanced" version named 0.9 was distrubuted on Compuserve earlier on January 1, 1991. This version is, according to Microsoft and unlike 0.9 DK, not compatible with later versions.

Version 1.0 was released some time after that, along with a Demonstration Applications distribution (WLO10.ZIP), containing WLO DLLs and the so-called Windows 3.0 accessory applets, which are ports of Calc, Calendar, Cardfile, Clipboard, Clock, Notepad, Paintbrush, Reversi, Solitaire, Windows Help, and Write from Windows 3.0. This is the only known preserved distribution of WLO, hence most of the information in this article is derivated from it, if not specified otherwise.

No later version is known to exist, and most likely it doesn't, since IBM and Microsoft parted ways later in 1991. OS/2 2.0 and later includes WinOS/2, which makes use 386 specific features; however, WLO 1.0 still works at least up to OS/2 Warp 4.5.