Distributed process networks — Using half FIFO queues in CORBA

Abstract

This chapter discusses distributed process networks. Process networks are networks of sequential processes connected by channels behaving like FIFO (first in, first out) queues. These are used in signal and image processing applications that need to run in bounded memory for infinitely long periods of time dealing with possibly infinite streams of data. This chapter discusses distributed implementation of this computation model. The implementation of a distributed process network by using distributed FIFOs to build the distributed application is discussed. The platform used to support this is the common object request broker architecture (CORBA) middleware. Indeed, each process of the process network can be written in a different language and run on a different hardware, provided that these are supported by the chosen object request broker (ORB). In addition of the heterogeneity, implementation presents the following characteristics; automation of data transfer between distributed processes, dynamic and interactive linking of the processes to form the data flow, hybrid data-driven, demand-driven data transfer protocol, with thresholds for load balancing, and the implementation was carried out, such as to enable a distributed or local execution without any change to the program source. A process network deployment and distributed execution is described. The transfer strategies (demand and data driven) are detailed.