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Local area networks - a merger of computer and communications technologies
Networks
Bernhardt, D and Schmitter, E 'Design and implementation of faulttolerant multimicrocomputer systems'
Microprocessors and Microsystems Aspelund, J
Vo15 No 4 (May1981) pp153
'Using dataflow in a system of multiple single board computers' Microprocessors and Microsystems Vol 5 No 3 (April 1981) pp 103-106
Multimicrocomputer systems, with their inherent hardware and software redundancies, are well-adapted to meet the fault-tolerant computing required by their users. This paper describes a basic fault-tolerant system (BFS) which with the special feature that each microcomputer module has bidirectional linkages to its next and next-but-one neighbours offers the best preconditions to solve the problems of fault tolerance with decentralized control, fault diagnosis on different levels and reconfiguration strategies. The partially meshed ring structure of BES has had qualified success under laboratory conditions.
The concept of dataflow is usually limited to totally new computer structures. This paper discusses the simulation of dataflow in a symmetric system of standard microcomputer modules. The approach has advantages in that the parallelism of the computation can be expressed and handled in a natural way. The simulation of the dataflow semantics takes hundreds of machine instructions for each actor execution so quite long actors are needed to keep the overhead low. The implementation of a dataflow computation using the adaptive trapezoid method for numerical integration is discussed. In this computation the total estimated overhead is less than 10 per cent.
Bass, C 'Local area networks - a merger of computer and communications technologies' Microprocessors and Microsystems Vol 5 No 5 (June 1981) pp 187-192
The development of local area networks has reached that crucial stage in its development when commercial implementation of systems becomes feasible. This article outlines the genealogy of LANs from interconnected remote mainframes to integrated networks, and examines system conformance to the International Standards Organization open systems interconnection reference model. A comprehensive survey of aspects of LANs is undertaken, including closed systems, choice of medium (e.g. twisted pair), signalling techniques (e.g. baseband or broadband), media access (will there be contention for the media and some resolution of that contention, or whether there will be a noncontention with allocation of the use and no real conflict - scheduled versus nonscheduled) and internetting. The article concludes with a look at the problems of security, administration and standards.
36
156
Braunleder, B and Kober, R 'Parallel processing with an array of microcomputers' Microprocessors and Microsystems Vol 5 No 6 (July/August 1981) pp241 245 New computer architecture aims at modularity, high performance and low operating cost, and demands new operating structures and software system design. SMS is a microprocessor-based structured multicomputer system which can effectively use up to several hundred microcomputers to solve large, mainly numerical problems. The operating scheme, system behaviour and communication protocols of the experimental SMS 201 are outlined in this article and particular emphasis is placed on the parallelization of problems to be solved and the high reliability of large arrays of identical microcomputers. SMS is seen as an economic alternative to mainframes, an option which the development of parallel algorithms and procedures and progress in VLSI, can only make more attractive.
Danhof, K J and Shah, V 'A multimicroprocessor architecture for industrial/process control applications' Microcomput. Applic. Vol 4 N o 4 pp 204--218 The main shortcomings of microprocessors when compared with hard-
wired logic and mainlrames is their slow speed and limited word size these limitations can often be overcome using multiprocessor architecture. This paper describes a low cost modular multimicroproccssor configuration. The system was designed specifically for industrial/process control applications and uses direct memory access (DMA) to facilitate the efficient transfer of data between processors. The system uses five identical 6800 microprocessors.
Ekanadham, K and Mahjoub, A 'Microcomputer networks' Comput. Vol 24 No I (February 1981) pp 17- 24 This paper presents an implementation of Hoare's I/O commands on a twodimensional network of microcomputers. The implementation is defined so that message transfer delays are bounded by a constant. The communication kernal is small and is embedded in each process. Dedicated processors are used For message handling, Areas looked at are communication, hardware and implementation (particularly a derivation of a constant upper bound on message transfer time). Example programs are also provided.
Roberts, M 'Multiprocessing networks vs. mainframes' parts one and two Mini-Micro Syst. Vol 13 No 19 pp 121- 128 and Vo113 No 11 pp 131-140 The first paper of this article describes the advantages of multiprocessing networks versus single mainframes. The article shows various methods to couple microprocessor systems to overcome system inefficiencies and complex interprocessor defects to make the networks commercially viable. The second part looks at, in more detail, the coupling process with emphasis on the closely coupled microprocessor schemes of CornegieMellon University and Digital Equipment and the cooperative looselycoupled architecture of Texas University's interactive database task.
Rolander, T 'CP/NET: control program for a microcomputer network' Micropro-
microprocessors and microsystems
Bernhardt, D and Schmitter, E 'Design and implementation of faulttolerant multimicrocomputer systems'
Microprocessors and Microsystems Aspelund, J
Vo15 No 4 (May1981) pp153
'Using dataflow in a system of multiple single board computers' Microprocessors and Microsystems Vol 5 No 3 (April 1981) pp 103-106
Multimicrocomputer systems, with their inherent hardware and software redundancies, are well-adapted to meet the fault-tolerant computing required by their users. This paper describes a basic fault-tolerant system (BFS) which with the special feature that each microcomputer module has bidirectional linkages to its next and next-but-one neighbours offers the best preconditions to solve the problems of fault tolerance with decentralized control, fault diagnosis on different levels and reconfiguration strategies. The partially meshed ring structure of BES has had qualified success under laboratory conditions.
The concept of dataflow is usually limited to totally new computer structures. This paper discusses the simulation of dataflow in a symmetric system of standard microcomputer modules. The approach has advantages in that the parallelism of the computation can be expressed and handled in a natural way. The simulation of the dataflow semantics takes hundreds of machine instructions for each actor execution so quite long actors are needed to keep the overhead low. The implementation of a dataflow computation using the adaptive trapezoid method for numerical integration is discussed. In this computation the total estimated overhead is less than 10 per cent.
Bass, C 'Local area networks - a merger of computer and communications technologies' Microprocessors and Microsystems Vol 5 No 5 (June 1981) pp 187-192
The development of local area networks has reached that crucial stage in its development when commercial implementation of systems becomes feasible. This article outlines the genealogy of LANs from interconnected remote mainframes to integrated networks, and examines system conformance to the International Standards Organization open systems interconnection reference model. A comprehensive survey of aspects of LANs is undertaken, including closed systems, choice of medium (e.g. twisted pair), signalling techniques (e.g. baseband or broadband), media access (will there be contention for the media and some resolution of that contention, or whether there will be a noncontention with allocation of the use and no real conflict - scheduled versus nonscheduled) and internetting. The article concludes with a look at the problems of security, administration and standards.
36
156
Braunleder, B and Kober, R 'Parallel processing with an array of microcomputers' Microprocessors and Microsystems Vol 5 No 6 (July/August 1981) pp241 245 New computer architecture aims at modularity, high performance and low operating cost, and demands new operating structures and software system design. SMS is a microprocessor-based structured multicomputer system which can effectively use up to several hundred microcomputers to solve large, mainly numerical problems. The operating scheme, system behaviour and communication protocols of the experimental SMS 201 are outlined in this article and particular emphasis is placed on the parallelization of problems to be solved and the high reliability of large arrays of identical microcomputers. SMS is seen as an economic alternative to mainframes, an option which the development of parallel algorithms and procedures and progress in VLSI, can only make more attractive.
Danhof, K J and Shah, V 'A multimicroprocessor architecture for industrial/process control applications' Microcomput. Applic. Vol 4 N o 4 pp 204--218 The main shortcomings of microprocessors when compared with hard-
wired logic and mainlrames is their slow speed and limited word size these limitations can often be overcome using multiprocessor architecture. This paper describes a low cost modular multimicroproccssor configuration. The system was designed specifically for industrial/process control applications and uses direct memory access (DMA) to facilitate the efficient transfer of data between processors. The system uses five identical 6800 microprocessors.
Ekanadham, K and Mahjoub, A 'Microcomputer networks' Comput. Vol 24 No I (February 1981) pp 17- 24 This paper presents an implementation of Hoare's I/O commands on a twodimensional network of microcomputers. The implementation is defined so that message transfer delays are bounded by a constant. The communication kernal is small and is embedded in each process. Dedicated processors are used For message handling, Areas looked at are communication, hardware and implementation (particularly a derivation of a constant upper bound on message transfer time). Example programs are also provided.
Roberts, M 'Multiprocessing networks vs. mainframes' parts one and two Mini-Micro Syst. Vol 13 No 19 pp 121- 128 and Vo113 No 11 pp 131-140 The first paper of this article describes the advantages of multiprocessing networks versus single mainframes. The article shows various methods to couple microprocessor systems to overcome system inefficiencies and complex interprocessor defects to make the networks commercially viable. The second part looks at, in more detail, the coupling process with emphasis on the closely coupled microprocessor schemes of CornegieMellon University and Digital Equipment and the cooperative looselycoupled architecture of Texas University's interactive database task.
Rolander, T 'CP/NET: control program for a microcomputer network' Micropro-
microprocessors and microsystems