It's true that there is no great answer for how to add capabilities and sandboxing after the fact. But what Windows did was build an incredibly restrictive sandbox and then tell everyone who couldn't accommodate even one of the restrictions was "sucks to be you". The result was that developers, when confronted with "all or nothing" for Metro-style apps, were forced to choose nothing. It was also not a good look that Microsoft's own flagship applications like Visual Studio and Office did not show any progress toward adopting UWP, and in the latter case, was specifically exempted from the Windows RT restrictions to continue using Win32 on that platform.

If there had been a better strategy for easing in UWP technology, we might have seen better progress on adoption of Windows Runtime APIs and capabilities so new programs could gradually move toward the new technologies and away from HWNDs. Unfortunately, the technical barriers that were put in place between Win32 and UWP are so large that progress toward breaking them down in the Windows App SDK has been slow.

From the native code side, it was not so great. The .NET 2.0 CLR had very poor support for hosting from the native side and really wanted you to make a program that was .NET first, it didn't work well if you wanted something like primarily a C++ program that hosted a C# UI in the same process. Reverse P/Invoke via native exports wasn't exposed, so creating DLLs for consumption by non-.NET programs was difficult. Mixed mode debugging was and still is painful, with the debugger being glacially slow at some operations like OutputDebugString() processing and blocking some native features like data breakpoints, and the CLR eating access violation exceptions from native code so they couldn't be debugged properly. Build-mode wise, we had to ban C++/CLI assemblies depending on C# assemblies because the C# project system didn't handle incremental builds properly and forced the dependent C++ assembly to rebuild all the time.

These issues still largely exist and are an issue with WPF. It's a great UI framework, but it's unusable unless your front end is primarily a C# program.

These were finally improved for WPF 4, since Visual Studio 2010 switched to it and had a near riot in the betas due to the poor rendering in the text editor.

When I first started porting programs to Windows ARM64, I didn't have an ARM64 device and had to test in QEMU. It ran extremely slowly, probably 1/50th of real time. All UWP programs like Calculator ran like a slug. But which programs still ran reasonably? Classic WinDbg and Task Manager. Two programs that were still plain Win32.

There are significant issues with Win32, namely its lack of a permissions and isolation and lack of hardware acceleration in the old windowing UI (User/GDI). But the idea that Win32 is inherently power inefficient is, IMO, just BS. Its roots go back to CPUs that were orders of magnitude slower than modern CPUs and there is nothing difficult about making a Win32 program that idles at 0% CPU when not in use.

> WinRT (2012) - it (or the embodiment in Windows 8) failed in the market but it also showed both the problem and potential solution to building for new markets while respecting the past

I can't express how wrong this is. WinRT was the most destructive thing that the Windows team ever did to the OS. It drove a hard stake into Windows, splitting it in half and declaring that anything previous to Windows 8, oriented toward desktop, or using primary input through mouse and keyboard over touch was dead. Microsoft basically told all existing Windows developers that if they weren't building a new, touch-oriented, mobile-style app specifically for Windows 8, they didn't matter and wouldn't get any support whatsoever, which is exactly what happened every time they broke existing desktop functionality. Calling this "respecting the past" is a crass insult and taking no responsibility for damaging the Windows development experience and accelerating development away from native Windows apps.

The Huffman decoding implementation is also bigger in production implementations for both speed and error checking. Two Huffman trees need to be exactly complete except in the special case of a single code, and in most cases they are flattened to two-level tables for speed (though the latest desktop CPUs have enough L1 cache to use single-level).

Finally, the LZ copy typically has special cases added for using wider than byte copies for non-overlapping, non-wrapping runs. This is a significant decoding speed optimization.

Win32 controls ignoring system colors goes much farther back than dark mode being introduced in Windows 10. The theming engine that broke a lot of that functionality was introduced in Windows XP. Beyond that, there were always a few hardcoded colors like disabled gray text going back to Windows 95.

Dark mode ignoring Win32 system colors is not incompetence. It was _intentional_. Dark mode was introduced by the UWP side, which intentionally did not extend it to Win32. To this day, there is not even a Win32 API for desktop apps to query whether dark mode is even enabled. The official recommendation is to compute the luminance of the UWP foreground color setting:

https://learn.microsoft.com/en-us/windows/apps/desktop/moder...

On top of this, there are a small handful of system UIs that do support dark mode and make your program look inconsistent with dark mode regardless. Message boxes will switch to dark mode, and so will file dialogs -- which is a problem if you've used the Vista-style customization, as any syslinks will appear in a color of blue that's hard to read against the dark mode background.

Winforms is also .NET based, so it's inaccessible if you don't want to write your UI in and take a dependency on .NET.

- Multiple monitors - Non-full screen views - Sideloading outside of the Store - Offline installation - Explicit threads - thread pool only - Aligned memory allocation - malloc only - Any C++ compiler other than MSVC - Support for any version of Windows other than Windows 8 - Running apps as administrator - Running more than one instance of an app at a time - Runtime shader compilation

If any ONE of these things was a blocker, you could not write a Metro style app. And yet Microsoft pushed this extremely hard -- including almost completely ending any maintenance of Win32 APIs. And despite the many relaxations and extensions, UWP is still largely useless today, and now even itself seems to be going into maintenance mode. All of which has done a lot of damage to the state of Windows desktop platform development.

As an example of how bizarre UWP is, for some reason every time they published a list of new APIs added to it, they converted the list of API identifiers to lowercase in the documentation:

https://learn.microsoft.com/en-us/windows/uwp/whats-new/wind...

It's relatively insignificant, but... why? Just one of many things that showed how immature UWP was.

L1D caches have also gotten bigger -- as big as 128KB. A Deflate/zlib implementation, for instance, can use a brute force full 32K entry LUT for the 15-bit Huffman decoding on some chips, no longer needing the fast small table.

The way that the vector registers were extended to 256-bit causes problems when legacy 128-bit and 256-bit ops are mixed. Doing so puts the CPU into a mode where all legacy 128-bit ops are forced to blend the high half, which can reduce throughput of existing SSE2-based library routines to as low as 1/4 throughput. For this reason, AVX code has to aggressively use the VZEROUPPER instruction to ensure that the CPU is not left in AVX 256-bit vector mode before possibly returning to any library or external code that uses SSE2. VZEROUPPER sets a flag to zero the high half of all 256-bit registers, so it's cheap on modern x86 CPUs but can be expensive to emulate without hardware support.

The other problem is that only the low 128 bits of vector registers are preserved across function calls due to the Windows x64 calling convention and the VZEROUPPER issue. This means that practically any call to external code forces the compiler to spill all AVX vectors to memory. Ideally 256-bit vector usage is concentrated in leaf routines so this isn't an issue, but where used in non-leaf routines, it can result in a lot of memory traffic.

Funny thing is that at the time, I was lamenting how much slower VC6 was than VC4. Macro playback, for instance, got much slower in VC6. It's all relative.