You know, NT was developed on the i960, a RISC chip from Intel that is now mainly found in printers, and once ran on AXP, PPC and MIPS in addition to x86. There was even a SPARC version. The decision to target only x86, ia64 and x64 now is purely a commercial one - people just didn't buy NT on anything else. And ISVs weren't interested in cross-compiling their software.
I actually used NT on AXP in the mid-90s. Kick-ass platform for SQL Server. But ultimately the momentum wasn't there.
Yes, but I believe those were all desktop systems or servers, weren't they? I was thinking more about limitations that make it difficult to adapt in resource constrained environments such as we find in today's smartphones. We do see Windows used in places such as ATMs (I got a great photo of one rebooting on me the other day, Windows icon and all!). But even Microsoft don't seem to want to use it in their portable gadgets. I for one do not have a good understanding of the issues that make this type of adaption difficult on Windows, or even if it's not a technical question, but rather a political one...
There is no technical reason that you couldn't run NT on anything you could run Unix on. It was architected from day 1 with a hardware abstraction layer (HAL) specifically for that. In theory, port the HAL (assembly language) then the rest is just a recompile. There's more to it than that (the SPARC version suffered severe performance issues due to endianness) but that's the general idea.
I expect Dave Cutler remembered that VMS (at the time) could only run on VAX, the OS and CPU were developed in tandem and VMS relied on some features not present on other CPUs (I don't recall exactly what offhand). It was a huge engineering effort to get it onto Itanic.
The main problem was that a single Alpha could replace an awful lot of VAX HW and so to claw the profit back, the license fees meant a VMS Alpha was about 3x the price of the same machine running NT.
We used to buy NT Alphas and install Linux - to compete with Sun Sparcs.
Wasn't the NT core the starting point for the XBox team? And the original XBox had fewer resources than today's mobile gadgets.
The only reason Windows hasn't been scaled into more segments well, is that Microsoft's bureaucracy doesn't allow it to be stripped to its core as with the Xbox. They insist on layering on the cruft as with Windows CE.
I ran NT3.5 on a 16MB Pentium machine at one point and it ran comfortably, true.
I also ran System/390 on 32MB of RAM a couple of years before that. That's no indication that System/390 is appropriate in any way or manner for the embedded world.
Windows 7 is not easily portable to a phone; That's why Windows Phone 7, a CE derivative, -- an entirely different codebase that MS has been maintaining for the last 15 years, exists.
I actually used NT on AXP in the mid-90s. Kick-ass platform for SQL Server. But ultimately the momentum wasn't there.