An Architecture Design and Assessment System
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The Architecture Design and Assessment System (ADAS) was a set of software programs offered by the Research Triangle Institute from the mid 1980s until the early 1990s.[1]
A petri net-like graph model of a system was graphically created. The hierarchical graphs were simulated to determine resource utilization and throughput. Functional simulation of the model could be realized by attaching C (programming language) or Ada (programming language) code to the nodes. This enabled dynamic resource assignment, timing, and priority.
[edit] Simulation Model
An ADAS model consisted of nodes connected by directed arcs.
For abstract simulation a node represents a process (systems engineering) in the system that you are modeling. The readiness for execution or firing of this process requires that: its inputs are satisfied, space is available for its outputs, and its shared resource/hardware is available. During execution the node consumes its inputs, uses the resource for the prescribed duration, then produces its outputs.
The inputs and outputs of a process are represented by discrete tokens. These tokens flow along the arcs in the graph. If the maximum arc size is greater that one, then an arc would respresent a buffer between system processes.
The refine the model of the system, a subgraph could be placed below the node to refine the behavior of that process.
Physical and behavioral properties were attached to nodes and arcs in the form of attributes. The attribute definition language allowed the computation of attributes from ancestor attributes and global values.
[edit] References
- ^ G.A. Frank, D.L. Franke, and W.F. Ingogly, "An Architecture Design and Assessment System,"VLSI Design, Vol. 6, No. 8, Aug. 1985, pp. 30-50
[edit] Further Reading
- Integration of Tools for the Design and Assessment of High-Performance, Highly Reliable Computing System (DAHPHRS) Phase 1, NASA Contract NAS1-17964, May 1992, page 141 http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920019342_1992019342.pdf
- The Practice of Prolog: a Prolog-based VLSI editor, Leon Sterling, 1990, ISBN 0262193019
- Aladdin Software Support, Proceedings of the IEEE 1991 National Aerospace and Electronics Conference
- Performance Analysis of a Large-Grain Dataflow Scheduling Paradigm, NASA Langley, June 1993, page 8 http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930023024_1993023024.pdf
- Virtual Prototyping, Digital Signal Processing Systems, 1998 Lockheed Martin Technology Symposium, slide 7 http://www.atl.lmco.com/projects/csim/vp4C.pdf