“Topologies”—distributed objects on multicomputers

• Authors: Karsten Schwan;Win Bo
• Venue: ACM Transactions on Computer Systems (TOCS)
• Year: 1990

Application programs written for large-scale multicomputers with interconnection structures known to the programmer (e.g., hypercubes or meshes) use complex communication structures for connecting the applications' parallel tasks. Such structures implement a wide variety of functions, including the exchange of data or control information relevant to the task computations and/or the communications required for task synchronization, message forwarding/filtering under program control, and so on. Topology is a programming and operating system construct that allows programmers to describe and efficiently implement such functionality as distributed objects with well-defined operational interfaces. As with abstract data types, topologies may be reused by any application desiring their functionality. However, in contrast to other research in parallel or distributed object-based operating systems, internally, a topology may be an entirely distributed implementation of the object's functionality, consisting of a communication graph and type-specific computations, which are triggered by messages traversing the graph. Sample computations may perform additions or minimizations of the values traversing a topology, thereby computing a global sum or minimum. Similarly, computations may concatenate or filter messages in order to implement program monitoring, I/O, file storage, or virtual terminal services.Topologies are implemented as an extension of the Intel iPSC hypercube's operating system kernel and have been used with several, large-scale parallel application programs.