Mastodawn

I discovered a wonderful hack that likely would allow me to run Windows 2 on my vintage Apricot PC Xi before the New Year.

Quick recap: Apricot PC is a British computer from 1983, not compatible with the IBM PC. It had a Windows 1 port, but not Windows 2, and thus couldn't run Word, Excel, or Illustrator. With a bit of driver-writing, I managed to start Windows 2 on it, but my video driver is rudimentary and cannot be used for practical purposes. Windows video drivers are super-complicated, so I was fully expecting to spend over a month writing one (at least there are docs for everything!)

But I just discovered a way to run Windows 2 with Windows 1 video drivers. So if I had a Windows 1 driver for Apricot, I could use it in Windows 2. Of course, it's never that simple...

Find the difference between Windows 2 with Win1 driver and Windows 2 with the real Win2 driver - both are EGA 640x350!

🧵 thread with a few more screenshots and pointers

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Nina Kalinina Dec 21

As you might know, graphical drivers for Windows 1/2/3 are _complicated_. They are expected to implement a huge chunk of Windows GDI, the graphical abstraction library. This means they're responsible for drawing parts of the window decorations, and so on.

You also might remember that Windows 1 had window decorations _completely_ different from Windows 2, as it was using tiled windows instead of overlapping ones. But for some reason, Windows 1 video drivers can render floating windows just fine, and even can draw minimize and maximize buttons.

However, Windows 1 drivers handle fonts in a different way. Windows 2 is supposed to offer a new Font API, but most apps are using the legacy entry point for ExtTextOut. The font format is completely different, though. So, imagine you transplant a Windows 1 driver to the Windows 2 system. The second screenshot is what you get.

(🧵2/? continue)

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mxk

@nina_kali_nina arguing that Windows 1 and 2 are very different since Windows 1 didn't support overlapping windows, isn't convincing to me.
From what I understand, Windows 1 originally did support overlapping windows and it took some serious effort to change this pretty late in the project.

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Nina Kalinina Dec 21

@mxk the early demo from Comdex shows overlapping windows, and there is a special window type that allows windows to be floating. They do not look like Windows 2 windows, though: http://toastytech.com/guis/miscbw1popups.png
So I'm baffled by the fact the driver has the resources for proper Presentation Manager-style interfaces 🤔 Gotta cross-check this somehow.

Regarding the hypothesis that tiling was added late in the development: the DR preview from May 1984 (more than a year before the official release) already had tiling by default. The demo from 1983 seems to support tiling, too.