Windows 3.1 in a Windows 95 Virtual Machine (2022)

https://www.geoffchappell.com/notes/windows/retro/extrawin.htm

by Lammy • 10 months ago

71 54 10 months ago

pram• 10 months ago

Windows 95 had a bunch of stuff from 3.1 built in too. You could use progman as the default shell, it had file manager, etc.

ranger_danger2• 10 months ago

Yep it was even an option during the initial setup.

dblohm7• 10 months ago

Windows 95's USER and GDI implementation was essentially an enhanced version of Win 3.1's. user32.dll and gdi32.dll were just thunking layers. The 16-bit components were guarded by a mutex named "Win16Mutex" to ensure serialized access to them from the 32-bit side.

cyberax• 10 months ago

This mutex also protected a lot of other stuff. For example, if you wanted to access a DirectDraw surface, you needed to lock it in RAM, and this acquired the Win16 mutex. So if you then called a GDI function to draw something, it deadlocked the machine.

dcrazy• 10 months ago

Reminds me of how even well into the PowerPC era, much of Mac OS was still written in 68000 assembler, including QuickDraw (the equivalent of GDI).

kristopolous• 10 months ago

The pressure to not fuck up windows 95 was immense. You have to appreciate the landscape then.

You had os/2 not doing that well, Amiga not doing great, NeXT hurting, riscos kinda floundering and the failures of Windows 1 and 2.

The risk of it not slapping was immensely high. A huge amount of the company was bet on it.

They were risk adverse all over the place with the design, it's clear to see when you do a deep dive.

And even then, people balked at things like the 8MB ram "recommendation", which was seen as expensive at the time.

Even after the release and into 1996, large vendors were still shipping some computers with windows 3.1 - it was an option.

It was really both a risky product and had to be done.

icedchai5• 10 months ago

Windows 95 was a game changer, especially for Internet connectivity. The built-in "dial up networking" / PPP was huge. I was working at an ISP at the time, and remember how difficult it was to get customers to download Trumpet winsock and set it up for Windows 3.x. It could take hours with a difficult customer.

qwerty456127• 10 months ago

You had os/2 not doing that well, Amiga not doing great, NeXT hurting

What was ever wrong with these? I never actually used them but everything I know about them sounds fantastic.

ranger_danger2• 10 months ago

I've never been so delighted to see Raymond proven wrong. And he doesn't even deserve to be proven wrong.

29athrowaway• 10 months ago

More impressive is the fact you can upgrade from Windows 1.0 all the way to the latest one. I am not a fan of Windows but I found this to be impressive.

https://www.youtube.com/watch?v=9f5DnlUyaq8

zamadatix2• 10 months ago

More impressive is the fact you can upgrade from Windows 1.0 all the way to the latest one.

That's no longer true since Windows 11 went 64 bit only (with no in place upgrade path as 16->32 bit had). E.g. the linked video starts a clean slate at XP in order to switch to 64 bit from that point on.

Still damn impressive one can make it all the way to Windows 10 (32 bit), but equally crazy IMO the upgrade story finally ended with 11.

bigwheels3• 10 months ago

It's actually appropriate for it to break with 11, since Windows 11 is the fork in the road where many of us stopped caring to use Windows anymore.

jamesu• 10 months ago

A while back I recall watching a video about this very feature. https://www.youtube.com/watch?v=SC3TVvtuNqs

burnt-resistor• 10 months ago

I'm betting those guest instances are Windows 3.1 Real Mode however and so cannot load most protected mode drivers. IIRC, there are a bunch of protected mode things like the VDM that take control over the system because there's no such thing as nested virtualization until about 2005-2006 when VMware and similar hypervisors pushed for it.

ashleyn• 10 months ago

The screenshot explicitly shows "386 Enhanced Mode" in the Windows 3.1 about dialog.

trollbridge• 10 months ago

The guest instances are fully 386 Enhanced Mode instances of Windows 3.1. Windows 3.1 (and Windows/386 and Windows 3.0) is implemented as an 80386 DPMI server, much like the DOS4GW you used to play Doom, and the the actual GUI code is a DPMI client. Windows 95 is also a DPMI server.

Windows 3.x could also run in “standard mode”, where it used a 16-bit only DPMI server. The Windows GUI system could run in real mode or as a DPMI client.

As far as “nested virtualisation”… Windows 3.1’s DOS windows could actually in turn run more instances of Windows 3.1, because Windows/386 relied on virtual 8086 mode only and Windows 3.x used DPMI which can be nested.

JdeBP2• 10 months ago

The protected mode drivers are already loaded in this scenario. The VMM and all of the VxDs are already up and running. All that's really happening here is the first VM (the "systemm VM") is running the DOS+Windows 95 kernel/user/gdi/system/network/display/keyboard and applications, and a second VM is running the DOS+Windows 3.1 kernel/user/gdi/system/network/display/keyboard and applications.

The former's VMM and VxDs were largely a superset of the latter's. The only real trick is that there was a secret handshake between the DOS program WIN and the Windows KRNL386 program that has to be satisfied by whatever tries to start it in that second VM, otherwise KRNL386 just exits immediately. One cannot use WIN to start KRNL386 in the second VM. WIN does too much other than running KRNL386. It has to be something else that does the secret handshake and only tries to run KRNL386.

kmeisthax• 10 months ago

There are, of course, a few caveats and a contrivance. Stick with me for Part Two and I will explain, including to give directions so that you can play too (with suitable hardware or emulators).

This article is 3-4 years old - any hint of Part 2? I'm assuming those nested copies of 3.1 are stuck in Standard Mode.

Lammy3• 10 months ago

https://news.ycombinator.com/item?id=37384911

Windows 3.1 in a Windows 95 Virtual Machine (2022)

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