Hi -
I believe that the HP NONSTOP systems run the NonStop OS? If so, then the answer is 'no'. MongoDB only supports Windows, OS X, Linux, and Solaris OS variants. If The NonStop OS offers a Linux personality, it might be possible to build MongoDB from source against it, however, it would not be a supported configuration. Additionally, I believe that some of the HP NONSTOP systems are Itanium based. MongoDB does not support Itanium on any OS.
Is the NonStop OS a POSIX environment? Are you planning on running on Intel x86, rather than Itanium? If the answers to those questions are 'yes', then it is more likely that a port would be possible.
Thanks,
Andrew