RPC clarification and recommendations

[powell at newyork.crd.ge.com]

I am an engineer and I have the task of trying to develop a system for
mechanical engineering design that involves running programming tools such
as fortran turbine design programs, compressor design programs, a C
database, and a rule system(s) on different platforms. These platforms are
IBM PC 386 or higher, Sun 4, HP, Decstation, and Vaxstation.  All of my
platforms are connected by TCP over ethernet.

My problem is which communication software do I use to develop the
client-server concept to run on each machine. I would appreciate any and
all comments that would enlighten me about the pluses and minus of any
given approach. Below I have listed some approaches that I have read about
but need clarification from you more experienced software experts on the
net.

1. I read about Sun's RPC which are suppose to allow the developer to
   concentrate on the application and not the network software. These sounded
   great in principle but is public domain RPC code available for the Vax
   (VMS and Unix lines) along with the IBM PC and HP. If yes then where can I
   get it? Suns manual says that RPC's have been run on these machines.

   To confuse me further, I understand that HP has a different version of
   RPC's then Suns. Does this mean that there are two different emerging
   standards? If yes then which is the one that appears to me winning?  Does
   each competitor also support the others standard?

2. Berkley sockets vs System 5 sockets. Should I deal at the socket level
   and which type of sockets should I use? To run a program on a IBM PC from
   a Sun which type of sockets do I need on the IBM PC. Do sockets come for
   free with the TCP, and if yes then which type of sockets are they, and
   does a software developer have access to the TCP library needed to use
   these sockets?

I appreciate any knowledge or pointers that I can use for helping me fill
out my knowledge so that I can concentrate on the best approach to my
problem.  I have obtianed the Unix Network Programming book by Stevens.
The book is excellent in describing the berkley sockets and TLI but I am
not sure about which to use or if they are at all applicable when I have a
VMS machine.

Regards
Dave