This is for historical reference as we switched to Linux in 2011
To select the platform to use we reviewed most of the opensource unix derivatives. We'd already decided that the OS must be opensource, and unix based. Windows NT was considered but the considerable architectural differences would have made the CPE a lot more complex.
- NetBSD is oriented around portability
- NetBSD is derived from BSD, and has a much more unix-like core. This also makes it closer to UNOS 8/9 which had some BSD compatability.
- NetBSD is smaller and more compact than the other *BSD derivatives.
- As simulation people we feel that NetBSD is more suited.
The Linux Port
Having originally developed under NetBSD we are now involved in porting SwiftIOS to Linux. Some of the reasons above are not as valid in 2011 as they were in 2001 and some of our customers have a requirements for OS approval, and most of these already have approved Windows 7, Windows Server and Linux.
Even when you Enable case sensitive behavior with Windows XP and Interix Subsystem or SFU there are many fundamental differences, some of which can be addressed with the SFU/Interix subsystem and some that can't.
After much consideration we have ruled out using SFU/Interix, it'll be in extended support from 2011 until 2014
So, if there is ever a Windows version of SwiftIOS it will be using a different architecture, with much more work in the emulation layer. We think it's still possible but a lot of work for little benefit