| 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[3] |
|
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[disambiguation needed] |
|
Terminal Services, Terminal Server |
Terminal Server adds "multiheading" support to Windows (the ability to run multiple instances of the graphics subsystem), and the hydra is a mythological monster with multiple heads. |
| Impala |
|
Windows NT 4.0 Embedded |
|
| N/A |
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 |
Windows Neptune |
N/A |
Ideas project, merged to Whistler. |
| Whistler |
|
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 |
A low-end version of Windows XP that is intended to be a thin-client that works with older hardware. Available through 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 |
|
|
Similar to Eiger, but supports Windows Mobile devices, Windows Image Acquisition, wireless networking, |