Question about start year of developing Windows

[Zenkaino lovelive]

Windows 95: from 1992
Windows 98: from 1996
Windows Me: from 1999

Windows 2000: from 1996
Windows XP: from 2000
Windows Vista: from 2001
Windows 7: from 2007
Windows 8: from 2009
Windows 8.1: from 2012
Windows 10: from 2014

I wonder the start year of developing the following Windows:
DOS/9x-family: 1.0, 2.0, 3.0, 3.1
NT-family: NT 3.1, NT 3.5, NT 3.51, NT 4

[Itsmeheena]

The development start years for the following Windows versions are:

DOS/9x-family:

MS-DOS 1.0: Developed around 1981.
MS-DOS 2.0: Developed around 1983.
MS-DOS 3.0: Developed around 1984.
MS-DOS 3.1: Developed around 1985.
NT-family:

Windows NT 3.1: Development began in 1989.
Windows NT 3.5: Development began in 1994.
Windows NT 3.51: Development began in 1995.
Windows NT 4: Development began in 1996.

[Zenkaino lovelive]

The development start years for the following Windows versions are:

DOS/9x-family:

MS-DOS 1.0: Developed around 1981.
MS-DOS 2.0: Developed around 1983.
MS-DOS 3.0: Developed around 1984.
MS-DOS 3.1: Developed around 1985.
NT-family:

Windows NT 3.1: Development began in 1989.
Windows NT 3.5: Development began in 1994.
Windows NT 3.51: Development began in 1995.
Windows NT 4: Development began in 1996.

I mean Windows 1.0/2.0/3.0/3.1, not MS-DOS 1.0/2.0/3.0/3.1.

[anonymous74]

This isn't completely correct - NT 4 has known builds from 1995, so it started at least then.

[Meow]

This isn't completely correct - NT 4 has known builds from 1995, so it started at least then.

Also Windows 10 definitely had builds from 2013. NT 4 probably started development as a project to port the Win95 shell to NT (3.1, and then 3.5)

[vbdasc]

IMHO,

Windows 1.0 - 1983
Windows 2.0 - 1986
Windows 3.0 - 1988 (as a hobbyist project; 1989 as a product)
Windows 3.1 - 1991

[Zenkaino lovelive]

I can say like below:

Windows 1.0 - started developing in 1983, released in 1985
Windows 2.0 - started developing in 1986, released in 1987
Windows 3.0 - started developing in 1989, released in 1990
Windows 3.1 - started developing in 1991, released in 1992
Windows 95 - started developing in 1992, released in 1995
(Nashville - started developing in 1994, but canceled)
Windows 98 - started developing in 1996, released in 1998
Windows 98 SE - started developing in 1998, released in 1999
Windows Me - started developing in 1999, released in 2000

Windows NT 3.1 - started developing in 1989, released in 1993
(Cairo - started developing in 1992, but canceled)
Windows NT 3.5 - started developing in 1993, released in 1994
Windows NT 3.51 - started developing in 1994, released in 1995
Windows NT 4 - started developing in 1995, released in 1996
Windows 2000 - started developing in 1996, released in 2000
(Neptune - started developing in 1998, but canceled)
Windows XP - started developing in 1999, released in 2001
(Longhorn Pre-reset - started developing in 2001, but canceled)
Windows Vista - started developing in 2004 (Longhorn Post-reset), released in 2007
Windows 7 - started developing in 2007, released in 2009
Windows 8 - started developing in 2009, released in 2012
Windows 8.1 - started developing in 2012, released in 2013
Windows 10 - started developing in 2013, released in 2015
Windows 11 - started developing in 2019-2020, released in 2021

Is the content above correct?

[anonymous74]

I don't know every development date to heart but:

You left out the Longhorn reset, 2004. Vista as we know it started in 04, although WinPE wasn't reset.
I doubt Windows 11 started that early, especially given the state it released in. Not sure though, if I had to guess when it began development I'd say late 2019 or early 2020 but I'm really not sure. 2018 seems off though. Where'd you source that from?

[Zenkaino lovelive]

Sources from internet search... I'll fix the incorrect parts!

[anonymous74]

Again - I came up the Windows 11 dates off the top of my head, they could be completely wrong. I'd wait until someone who knows for sure chimes in before assuming that I'm correct. I just think 2018 is too early and then made a guess.

[AlphaBeta]

(Neptune - started developing in 1998, but canceled)

I would say work on Neptune only started in early 1999.

You left out the Longhorn reset, 2004. Vista as we know it started in 04, although WinPE wasn't reset.
I doubt Windows 11 started that early, especially given the state it released in. Not sure though, if I had to guess when it began development I'd say late 2019 or early 2020 but I'm really not sure. 2018 seems off though. Where'd you source that from?

Remember that Sun Valley was originally supposed to be a Windows 10 feature update (and it shows). Definitely 2020 at the earliest.

Offtopic Comment

WinPE wasn't reset.

WinPE predates Longhorn as a whole...

[anonymous74]

Really, it does?
When did PE start development because it first appeared to my knowledge during longhorn m4

[AlphaBeta]

...we literally have Whistler PE though?

[rafaelgs]

Really, it does?
When did PE start development because it first appeared to my knowledge during longhorn m4

FYI
It is worth noting: WinPE != WIM-based setup.

[anonymous74]

ah right