NWSRFS is transitioning from UNIX-based to a Linux-based operating system.
The reason for this, primarily, is that the National Weather Service AWIPS is transitioning to Linux.
There are several reasons for this transition:
First, the cost of Linux hardware and support is less than for UNIX.
Second, with regard to hydrology, NWSRFS runs much faster on Linux (as much as 32 times faster).      link here for details
Also, preliminary tests indicate that software for the Advanced Hydrologic Prediction System (AHPS) and for dynamic routing (fldwav) also run faster on Linux.

Because of the architecture difference between the PC and the workstation, binary files are not compatible between UNIX and Linux.
The implication here is that you cannot mix HPUX and Linux files and therefore NWSRFS running on Linux must use only Linux files in the OFS database.
Operators/forecasters should not, however, see any differences in operational characteristics.

A W2K version of NWSRFS has been developed to run on laptops which have Windows 2000 or Windows XP.
This version appears to be quite stable and quite fast also.
The program has the same look and feel of the UNIX version of NWSRFS presently running at River Forecast Centers (RFCs) except for automated data handling.
The W2K version of NWSRFS requires manual data input, but this is not a major issue if there are not many stations involved.