Windows codenames

Windows 3.1x/9x

Codename	Preliminary name	Final name	Notes
Janus		Windows 3.1
Kato, Sparta		Windows for Workgroups
Snowball (LB)		Windows for Workgroups 3.11
Chicago	Windows 4.0	Windows 95
O'Hare		Internet Explorer, first shipped in Microsoft Plus! for Windows 95	O'Hare is the main airport for the city of Chicago.
Frosting		Microsoft Plus! for Windows 95
Detroit		Windows 95 OSR 2
Nashville	Windows 96	Internet Explorer 4.0	Cancelled upgrade for Windows 95; sometimes referred to in the press as Windows 96. Codename was reused for Internet Explorer 4.0 which incorporated many of the technologies planned for Nashville.
Memphis	Windows 97	Windows 98	easter egg in Windows 98: open the "Date and Time" control panel; go to the "Timezone" page; hold the Control key and drag a line with the mouse cursor from Memphis, Egypt|Memphis, Egypt (or maybe Cairo, codename of Windows NT 4 - the map is too small to tell) to Memphis, Tennessee|Memphis, Tennessee. Still holding the Control key, drag another line from Memphis to Redmond, Washington; a window (computing)|window opens with the credits for Windows 98.
Dolly		Windows 98 OEM/Corporate image cloning utility	Dolly refers to Dolly the Sheep, the first sheep to be cloned.
Millennium	Millennium	Windows Me	Me stands for Millennium Edition

Windows NT family

Codename	Preliminary name	Final name	Notes
NT OS/2	OS/2 3.0	Windows NT 3.1
Daytona		Windows NT 3.5
SUR (Shell Update Release), Cairo[1]		Windows NT 4.0	Microsoft originally planned for NT 4.0 to be just a simple "Shell Update Release" to integrate the Windows 95 GUI with Windows NT 3.51's kernel.
Wolfpack		Microsoft Cluster Server
Hydra		Terminal Services, Terminal Server	hydra is a mythological monster with multiple head (anatomy)|heads.
Impala		Windows NT 4.0 Embedded
	Windows NT 5.0	Windows 2000	A watershed in Windows naming: first major Windows release since Windows 3.0 without a codename; first major Windows NT release whose client variant was named "Professional" instead of "Workstation"; first major Windows NT release without the "NT" designation in the trade name, which caused confusion when Windows ME was released. The original Windows line (Windows 9x) has since been dropped altogether, and Windows NT operating systems since then are simply referred to as "Windows".
Asteroid		Windows 2000 Service Pack 1
Janus		Windows 2000 64-bit	Same codename as Windows 3.1
Odyssey		N/A	Ideas project, merged to Whistler.
Neptune		N/A	Ideas project, merged to Whistler.
Whistler	Windows .NET 2001	Windows XP	Merge of Whistler build 2202, Neptune and Project Odyssey. Named after Whistler, British Columbia, where design retreats were held.
Mantis		Windows XP Embedded
eHome		Windows XP Media Center Edition
Freestyle		Windows XP Media Center Edition 2003	Name of a terrain rating system in the Whistler-Blackcomb resort.
Harmony		Windows XP Media Center Edition 2004	Name of a ski lift and alpine bowl in Whistler, British Columbia.
Symphony		Windows XP Media Center Edition 2005	Name of an alpine bowl in Whistler, British Columbia.
Emerald		Windows XP Media Center Edition 2005 Update Rollup 2	Name of a ski lift in Whistler, British Columbia.
Trainyard		Windows XP Service Pack 1	Trainyard was an engineering package of driver updates to ship simultaneously with Windows XP Service Pack 1, the most major of which was support for USB 2.0 which was also ported backwards to Windows 2000.
Springboard		Windows XP Service Pack 2	Name of a ski run on Blackcomb in Whistler, British Columbia.
Lone Star		Windows XP Tablet PC Edition 2005	A branch of the Windows XP Professional Service Pack 2 codebase, featuring enhancements specifically for Tablet PC hardware.
Whistler Server	Windows XP Server, Windows .NET Server	Windows Server 2003	One of many unrelated Microsoft projects of the time to carry a ".NET" designation. See: Microsoft .NET.
Bobcat		Windows Small Business Server 2003	Bobcat is a ski-run on Whistler Mountain.
Eiger		Windows Fundamentals for Legacy PCs	Software Assurance program. The Eiger is a mountain in the Bernese Oberland in Switzerland. The Eiger is part of a trio of mountains, The Eiger, The Mönch and The Jungfrau.
Mönch			wireless networking, Virtual private networks|VPN-s and advanced IP (Internet Protocol) security. The Mönch is a mountain in the Bernese Oberland in Switzerland. The Mönch is part of a trio of mountains, The Eiger, The Mönch and The Jungfrau.
Longhorn		Windows Vista	Went gold (RTM) on 8 of November 2006. Named after the Longhorn Bar in the Whistler-Blackcomb resort; initially planned as an "interim release" between "Whistler" and "Blackcomb" (which was "Vienna" and is now Windows 7).
Cougar	Windows Small Business Server "Longhorn"		In development. Cougar is a ski-run on Whistler Mountain.
Longhorn		Windows Server 2008	In development. Planned server equivalent of Windows Vista to be released in 2008.
Centro			In development. Planned "mid-size" (25-500 PC) edition of Longhorn Server.[2].
Blackcomb, Vienna	Windows 7		Originally codenamed "Blackcomb" after the Whistler-Blackcomb resort. Renamed to "Vienna" in January 2006.
Q, Quattro		Windows Home Server	Announced at CES 2007. Original project codename was "Quattro" because it was the leader of the project's 4th attempt at building a home server at Microsoft. Renamed to Q once the project moved out of incubation stage.
Jupiter		Windows 8
Metro		Windows 8 Style UI	Renamed from Metro because of a lawsuit with the German Metro company
Blue		Windows 8.1