This paper gives an overview of the INCAS (INCremental Architecture for 
distributed Systems) multicomputer project, which aims at the development of a 
comprehensive methodology for the design and implementation of locally 
distributed systems. A structuring concept for distributed operating systems 
has been developed and integrated into the system implementation language 
LADY. The concurrent high-level programming language CSSA, based on the actor 
model, has been designed for the implementation of distributed applications. A 
substantial effort in the INCAS project is directed towards the development of 
a distributed test methodology. An experimental system has been implemented on 
a network of ten MC68000 microcomputers. Preliminary experience with the 
methodology has been gained from a small number of prototype applications.