A poor week for payment systems 02 September 2010 4:27PM Beverley Head Access of any sort has been a challenge for banks in recent days. Just a week ago ANZ's in-store eftpos system went awry for several hours leaving merchants and customers frustrated. ANZ is not alone in suffering computer crashes - on Monday this week CBA's eftpos and ATM network went haywire for a good part of the day, despite the Commonwealth's much vaunted core systems overhaul. Westpac's online banking platform was unavailable yesterday for nine hours.The problem for all the banks is that technical innovation at the customer interface is of no value at all if clients can't access the back-end information systems where their account data is stored.Computer outages lasting hours are now rare among best practice global data centres, which regularly score uptime scores of 99.5 per cent and above. Outages lasting more than a few minutes at a time are well below global best practice levels.As the ANZ must know, the launch of nifty iPhone applications won't overcome the problem of core systems being unavailable.When back-end data is available though, new technology can be seductive, as the 31,000 downloads attest.