BlackBerry manufacturer RIM has failed to answer a series of key technical questions about its catastrophic three day outage, which it has warned could take more time to fix.

In spite of RIM issuing a statement last night that a switch had caused the problems, Stephen Bates, the company’s UK managing director, said staff at the Slough datacentre did not know the cause. They "thought they had found the problem but had not", he said.

As the outage spread to the US and Canada, CIO sister title Computerworld UK asked RIM a series of questions about the outage, but received no response.

In spite of the three day outage hitting millions of customers around the world, RIM has not answered:

1) The exact nature and location of the problem

2) Which vendor made the switch device, if this was the cause

3) Where the failover site is located, and why a failover did not happen

It also failed to state if an upgrade preceded the problem. The Guardian newspaper reported today that the initial outage may have followed a software upgrade to a RIM database that led to corruption problems. Attempts to switch back to an older version of the database led to a collapse, it suggested.

In 2008, a major RIM outage in the US disconnected 12 million BlackBerry customers. Following that incident there were criticisms that the large US customer base was too reliant on RIM's main datacentre in Waterloo, Canada. In 2009, RIM opened an extra data centre in Texas and started building another one in Atlanta. Other regions appear to rely on the single datacentre in the UK.

As Bates apologised at an ‘innovation’ event today to his seven million UK customers for the ongoing three day service outage, the company is facing growing calls for possible compensation for customers.

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