Is a computer failure better than a hydraulic failure on an aircraft?

The media reported today that an Air India Airbus 319 made an emergency landing in Pakistan. Visit

http://www.ndtv.com/article/cheat-sheet/relieved-air-india-passengers-back-in-delhi-after-emergency-landing-in-pak-top-10-facts-240992

The first reports said that three hydraulic systems had failed simultaneously. Later reports said that actually wrong information had been given by the computers to the pilot; the hydraulic systems were OK, but the pilot got a misleading warning. He had no choice but to make an emergency landing. How can such a thing happen? Computer systems on modern aircraft are supposed to be protected against failure by redundancy. Multiple computers built by different manufactures and running different software systems are installed on each aircraft. This is supposed to prevent a problem being created by a failure in a single computer. The probability of multiple, independent computers making the same mistake simultaneously is calculated to be negligible. Some information on this topic can be found in the article:

http://en.wikipedia.org/wiki/Airbus_A320_family

The references in the article cited above give more information. 

Coming back to India, a speedy investigation should be carried out by the Government of India and the findings made public. There is hope that this will take place; there is a site describing in some detail aircraft accidents over the years in India:

http://dgca.nic.in/accident/content.htm

I would feel happier if complete documents revealing the findings of such investigations are made available over the Web.

In any case, best of luck to you and to me when we take the next flight! I would be taking one soon! 

Srinivasan Ramani