The OS/2 Museum just posted a three-volume set of draft Windows Presentation Manager reference documentation. This refers to the OS/2 Presentation Manager GUI but highlights the story Microsoft pushed in 1987: Windows and OS/2 both used the same graphical user interface called “Windows Presentation Manager”.
By the time OS/2 1.1 was released, the “Windows” part was dropped and the GUI was called simply Presentation Manager. And conversely Windows dropped the “Presentation Manager” moniker again and went back to being simply Windows.
But for a while, users were going to be able to run the same Presentation Manager applications on top of either DOS or OS/2, and developers only needed to design a GUI application once. Practice clearly does not always follow theory.
The preliminary OS/2 Presentation Manager documentation was almost certainly published in July 1987. That meant it predated the release of OS/2 Presentation Manager by more than a year, and in fact even predated the release of Windows 2.0 by a few months.
The references at the outset say that “it is strongly recommended that the documentation be read for informational purposes only”. Nevertheless, it is valuable historical documentation showing the Presentation Manager design as it existed in mid-1987, about nine months before the first beta version of Presentation Manager was even available (in the MS OS/2 SDK 1.03 release of April 1988).
The documentation still refers to “DOS” in many places when it’s clearly talking about OS/2 (for example, “a DOS module definition file”). This goes back to the times when OS/2 was called DOS 5, so as to distinguish it from the “legacy” DOS 3 and multitasking DOS 4, of course. There are notably no screenshots in the documentation, only ASCII art mock-ups of GUI windows.
The references do not contain only programming information. A fairly detailed description of the user interface and basic Presentation Manager applets is also included. Volume 3 then on the other hand contains device driver programming information, which was not part of the released Presentation Manager programming documentation (it was documented separately in a DDK).