Paper Announcement: Assigning Types for Processes

We are pleased to announce the following technical report 


               Nobuko Yoshida and Matthew Hennessy

         (Sussex Computer Science Technical Report, 99.02)

is available from 

   http://www.cogs.susx.ac.uk/                  (Sussex University)
   http://www.mcs.le.ac.uk/~nyoshida/paper.html (Leicester University)

Your comments are warmly welcome. 

Nobuko Yoshida 
University of Leicester

----------------------------- ABSTRACT ------------------------------

In wide area distributed systems it is now common for higher-order
code to be transferred from one domain to another; the receiving host
may initialise parameters and then execute the code in its local
environment. In this paper we propose a fine-grained typing system for
a higher-order pi-calculus which can be used to control the effect
of such migrating code on local environments.  Processes may be
assigned different types depending on their intended use.  This is
contrast to most of the previous work on typing processes where all
processes are typed by a unique constant type, indicating essentially
that they are well-typed relative to a particular environment.  Our
fine-grained typing facilitates the management of access rights and
provides host protection from potentially malicious behaviour.

A process type is essentially an interface limiting the resources to
which it has access, and the types at which they may be used.
Allowing resource names to appear both in process types and process
terms, as interaction ports, complicates the typing system
considerably. For the development of a coherent typing system, we use
a kinding technique, similar to that used by the subtyping of the
system $F$, and order-theoretic properties of our subtyping relation.

Various examples of this paper illustrate the usage of our
fine-grained process types in the distributed systems.

 Nobuko Yoshida                          E-Mail: ny11@mcs.le.ac.uk
 Dept. of Mathematics & Computer Science Tel: +44 116 252 3895 (direct) 
 University of Leicester     		 Fax: +44 116 252 3604 or 3915
 Leicester, LE1 7RH, England             http://www.mcs.le.ac.uk/~nyoshida