The magazine
Information Week, has an assessment that references the same final report and highlights the software programming error:
... according to the final report on the incident from the ATSB, the problem wasn't just a faulty ADIRU, but also a programming error involving the flight computers. In particular, the airplane software wasn't written to handle an event in which an ADIRU began outputting erroneous data at regular intervals.
Notably, the flight computers averaged the angle of attack data from two of the ADIRUs to compute the airplane's true angle of attack. If the data from the two ADIRUs significantly differed, however, then the flight computers discarded the values and used the one they'd computed 1.2 seconds prior. But investigators said that the algorithm couldn't handle an episode in which an ADIRU began feeding erroneous information at 1.2-second intervals. That led to the flight computers computing an incorrect angle-of-attack reading, causing it to execute the two dives, one of which subjected passengers to forces of 0.8 G.
They then report on the rarity of the event but programming was a key factor of the upset, once the initial failure had occurred.
The article is here:
Software Bug Triggered Airplane Dive Emergency - Security - Application Security - Informationweek