Comment by mananaysiempre

Comment by mananaysiempre 3 days ago

Hmm. IME VB6 is actually a particular pain point, because MDAC (a hodgepodge of Microsoft database-access thingies) does not install even on Windows 10, and a line-of-business VB6 app is very likely to need that. And of course you can’t run apps from the 1980s on Windows 11 natively, because it can no longer run 16-bit apps, whether DOS or Windows ones. (All 32-bit Windows apps are definitionally not from the 1980s, seeing as the Tom Miller’s sailboat trip that gave us Win32 only happened in 1990. And it’s not the absence of V86 mode that’s the problem—Windows NT for Alpha could run DOS apps, using a fatter NTVDM with an included emulator. It’s purely Microsoft’s lack of desire to continue supporting that use case.)

p_ing 3 days ago

> It’s purely Microsoft’s lack of desire to continue supporting that use case.

NTVDM leverages virtual 8086 mode which is unavailable while in long mode.

NTVDM would need to be rewritten. With alternatives like DOSBox, I can see why MSFT may not have wanted to dive into that level of backwards compat.

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mananaysiempre 3 days ago

As I’ve already said in my initial comment, this is not the whole story. (I acknowledge it is the official story, but I want to say the official story, at best, creatively omits some of the facts.)
NTVDM as it existed Windows NT (3.1 through 10) for i386 leveraged V86 mode. NTVDM on Windows NT (e.g. 4.0) for MIPS, PowerPC, and Alpha, on the other hand, already had[1] a 16-bit x86 emulator, which was merely ifdefed out of the i386 version (making the latter much leaner).
Is it fair of Microsoft to not care to resurrect that nearly decade-old code (as of Windows XP x64 when it first became relevant)? Yes. Is it also fair to say that they would not, in fact, need to write a complete emulator from scratch to preserve their commitment to backwards compatibility, because they had already done that? Also yes.
[1] https://devblogs.microsoft.com/oldnewthing/20060525-04/?p=31...

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anthk 2 days ago

ReactOS' NTVDM DLL wll work under XP-10 and it will run some DOS games too.

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drxzcl 3 days ago

Wait, what's the story of the sailboat trip? My searches are coming up empty, but it sounds like a great story.

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mananaysiempre 3 days ago

Yeah, I was surprised by the lack of search results when I was double-checking my post too, but apparently I wasn’t surprised enough, because I was wrong. I mixed up two pieces of Showstopper!: chapter 5 mentions the Win32 spec being initially written in two weeks by Lucovsky and Wood
> Lucovsky was more fastidious than Wood, but otherwise they had much in common: tremendous concentration, the ability to produce a lot of code fast, a distaste for excessive documentation and self-confidence bordering on megalomania. Within two weeks, they wrote an eighty-page paper describing proposed NT versions of hundreds of Windows APIs.
and chapter 6 mentions the NTFS spec being initially written in two weeks by Miller and one other person on Miller’s sailboat.
> Maritz decided that Miller could write a spec for NTFS, but he reserved the right to kill the file system before the actual coding of it began.
> Miller gathered some pens and pads, two weeks’ worth of provisions and prepared for a lengthy trip on his twenty-eight-foot sailboat. Miller felt that spec writing benefited from solitude, and the ocean offered plenty of it. [...] Rather than sail alone, Miller arranged with Perazzoli, who officially took care of the file team, to fly in a programmer Miller knew well. He lived in Switzerland.
> In August, Miller and his sidekick set sail for two weeks. The routine was easy: Work in the morning, talking and scratching out notes on a pad, then sail somewhere, then talk and scratch out more notes, then anchor by evening and relax.
(I’m still relatively confident that the Win32 spec was written in 1990; at the very least, Showstopper! mentions it being shown to a group of app writers on December 17 of that year.)

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