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Comment by Crinus | Hacker News Reader

I'm pretty sure it is the other way around, the OS/2 GUI (Presentation Manager) API is a cleaned up version of the Windows 2.x API.

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Sort of. IBM really wanted to ensure that OS/2 had an imaging model that was compatible with what it used in some of its larger computers. This resulted in a bunch of differences between OS/2's imaging model and GDI. (Different window origin coordinates, etc.)

In a more Microsoft-centric world, I'm pretty sure the OS/2 API would've been exactly as you describe it and almost strictly in parallel with Windows. In fact, Microsoft did exactly this with Win32s (and Windows 95) In their relationship with Windows NT (which was once known as OS/2 NT or OS/2 3.0).

The same compiled binary could run on both the 'entry level' OS and the 'server level' OS, with a bit of care taken in the way the API was used.

Once Microsoft agreed to the graphics api change, it was open season to redesign the window manager api because backward compat was moot at that point. The OS/2 window manager api was designed by the same team who designed the win16 window manager apis. There were improvements and a bunch of api change but at the 10K foot level the model was the same - input loop, window messages, and window procs.

> at the 10K foot level the model was the same - input loop, window messages, and window procs.

That's a fairly broad description, isn't it? At least I have a hard time coming up with windowing API models that don't fundamentally work that way at the lower levels. (About the only exception think of is a text-based library that shipped with Microsoft BASIC 7.0, and that was mainly because the language didn't support any of the abstractions needed for callbacks.)

That's a fair point, I'll restate: the level of abstraction that developers were exposed to was 95% the same. Exposed message loops, window classes, window messages, unpacking window params, post and send message semantics, painting, single cooperative input queue (window app hanging would hang all apps), and other equivalences.

The Win is just one layer in the OS/2 API and suspect you might be right in that this layer was probably modeled on early Windows.

However OS/2 had many other layers to it's programming SDK that were not found in early Windows.

For example there was the Dos layer for things like processes, threads, semaphores, files, directories etc.

And then there was the Gdi layer for graphics.

Most of that functionality only made it's way into Windows with the advent of Windows NT (Windows 3.x/95 had poorer versions of those functions. For example running a process and capturing it's output was a real pain in Windows 3.x and Windows 95).

And based on the fact so many of those OS/2 Dos function have an equivalent Windows NT version I suspect Microsoft used that OS/2 design as their starting point for NT.

As just one of many examples consider DosCreateThread from OS/2 1.x

http://www.edm2.com/index.php/DosCreateThread_(OS/2_1.x)

It looks a lot like the CreateThread function found in Win32:

https://docs.microsoft.com/en-us/windows/win32/api/processth...

Right, this is why i explicitly said "the OS/2 GUI (Presentation Manager) API" and not the entirety of OS/2. The original comment mentioned "was there any better GUI programming layers" after all.

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