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pnp-software / cordetfw

C Implementation of a Software Framework for Service-Oriented Applications with PUS Support
Mozilla Public License 2.0
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Rejection Criterium for (3,1) Command #138

Open pasetti opened 5 years ago

pasetti commented 5 years ago

Command (3,1) is used to create a new housekeeping report. One of the rejection criteria for this command is (see clause 6.3.3.5.1d): "the same parameter is identified more than once in that request".

The on-board implementation of this rejection criterium is very onerous. As an example, consider the case of a request to create a new housekeeping report with 2-300 parameters. This would require the on-board software to implement an algorithm to sort the 2-300 parameters and then to verify that the same parameters never occurs twice. Schedulability analysis would have to be done taking into account the worst-case execution time of such an algorithm. Is this something that should be done on-board?

I would propose that this rejection criterium be dropped. Note that failure to comply with this criterium would not put the integrity of the on-board software at risk (the only effect is a small waste of telemetry bandwidth).

pasetti commented 5 years ago

An alternative implementation would relay on an array of flags with one element for each parameter ID. The setting of the flag determines whether the parameter ID has been selected for inclusion in the housekeeping report. This implementation would probably be feasible.