Whistler came about when Microsoft merged their Neptune and Odyssey (the future version of Windows 2000 Professional) projects in January 2000. Rightly so, I think. The projects were similar enough and had similar goals, and Microsoft saw the benefits of unifying their development projects in that both OSes shared the same codebase and ambitions. Thus was born Whistler, or Windows 2001, or, as some might have it, Windows .NET 1.0.

Paul Thurrott has a good writeup about what exactly happened here...

Anyway, Whistler has had an interesting history so far. Somebody inside Microsoft leaked two very early Whistler builds early in 2000 - build 2211 hit the Web in March, and build 2223.1 hit the Web in April. I've never seen 2211 (few have), but I have used 2223.1 quite a bit. It's not even rightly a beta, or even an alpha build - it's just an internal build Microsoft used for testing (apparently they do new builds all the time, and only the best/most stable/etc of them get officially released as betas or previews or whatnot). Suffice it to say 2223.1 was a bit buggy. Explorer would crash if you looked at it funny, and a lot of applications didn't run right or simply refused to install. Nevertheless it was interesting to see where MS were going with Whistler, even this early in the game (Windows 2000 final was build 2195, so this Whistler build is only 28 builds onward from Win2K final...).

SETUP

Basically the exact same as Win2K. They didn't even bother changing the titles (i.e. "Windows 2000 Professional" is pervasive throughout the setup process, as opposed to "Whistler" or something). I didn't bother taking screenshots so you'll just have to bear with me on this. It even installs itself in the NTLDR boot menu as "Microsoft Windows 2000 Professional".

GENERAL OPERATIONS

This is where things get interesting.

     
 Logging in... similar to Neptune The desktop, very similar to Win2K Whistler 2001?

     
 About...  System properties  The simplified Control Panel

     
 File a bug report... for Neptune???  Help and Support... from Windows Me?  the Logon.scr screen saver

     
 The Explorer Show in Groups feature  New panel in Task Manager  Note the digital signer

     
 My Pictures screensaver New Web View in folders Personalized Notifications and Remote Desktop

     
 Start panel - note the dialog...    

Build 2223.1 was just a taste of what was to come... for that, follow me here to Whisler Professional build 2250, the Developer's Preview released by Microsoft on July 13, 2000.