An emerging belief among many researchers is that a significant portion of the next generation of high performance computers will be based on architectures capable of exploiting very large scale integration (VLSI) modules. In particular, it is desirable to have a compact system that can be plugged in with interchangeable high performance modules to fit various application requirements. The system can be an efficient signal processor when special purpose signal processing modules are used; it can also be an efficient database machine when the modules are replaced with data processing modules. This paper discusses some of the issues in the design of such a system, and describes the framework of a system that is being developed at CMU.