Citation
Abstract
As a final step in the operations analysis of Intermediate Data Record (IDR) production capability, dynamic system simulation models have been constructed and executed within the context of the General Purpose Simulation System (GPSS) applications program on the Univac 1108 system. The dynamic models simulate all activity in the DSN ground systems which contributes to data flow characteristics and ultimate throughput times for the IDRs. Two basic model versions have been constructed, representing alternative configurations at the merge processor: Model A simulates 4 tape-drive units at the merge processor; Model B simulates 8 tape-drive units. It has been confirmed subsequently that the 8 tape-drive configuration will be implemented. Both basic models were “‘driven,”’ in dynamic simulation runs, by the same “‘worst case”’ mission support profile, representing the heaviest possible support requirement during the Viking encounter and planetary experiment period. Quantitative specification for system parameters, flow logic, and support profiles has been derived from internal JPL documents. Much of the essential specification for dynamic models was immediately at hand as a consequence of earlier ‘‘static’’ analysis studies. A 4 tape-drive configuration was found to meet a 24-hour throughput time requirement for IDRs. However, the simulated facilities are heavily loaded by the ‘‘worst case’’ profile; therefore, significant deviations from assumed facility availability or operational capabilities may have a critical effect upon performance to the requirement, With an 8 tape-drive configuration, the Merge Processor easily meets the throughput time requirement. The simulated facilities show no severe utilization
Details
- Volume
- 42-29
- Published
- October 15, 1975
- Pages
- 191–204
- File Size
- 1.3 MB