Confusion on TSO's seems rampant. It reminds me of the confusion over "mass" and "weight".

TSOs are the Technical Standards that a device must meet to be considered to be said device by the FAA. TSO compliance has little to do with reliability.

DO160 is a collection of tests that can be performed on a device to demonstrate that it is robust. Being able to pass these tests is an indicator of how reliable a device will be once installed.

DO178 controls the testing and certification of software.

Certification is a process by which you demonstrate to the FAA that a given device complies with the applicable TSO and/or will pass the applicable DO160 tests and/or will satisfy the applicable DO178 level standards.

Reliability is a generic qualitative term that implies a device will perform as expected when subjected to anticipated conditions. Can you rely on a device to perform as expected.

Robustness or ruggedness is a device's ability to perform after being subjected to conditions beyond what is normally anticipated.

A device can comply with a TSO and not be TSOed. A device can pass DO160 testing and not be "Certified".

Regards
Brent Regan