The Commonwealth Bank's technology bill crept up six per cent during the last 12 months to A$1.38 billion - largely due to a faster rate of software amortisation ($328 million in the last financial year) and $70 million worth of software write-offs during the year.Traditionally that sort of burn rate could be seen as the mark of technology failure - but given the rate of digital disruption in the financial sector, it should probably be interpreted as the cost of rapid technical innovation for a bank which likes to position itself at the front of the technology pack.Even after the accelerated amortisation the bank still has $1.8 billion worth of software on its books.CEO Ian Narev yesterday pointed to the slew of apps, back office systems, online capabilities and payments platforms the bank has rolled out or has under development. This has delivered it five million active online customers while its apps are used by 2.6 million people.Having concluded its core banking overhaul under the stewardship of former chief information officer Michael Harte (now at Barclays in the UK), CBA is well placed to roll out new systems and products swiftly.The technology overhaul has also established a more robust computing infrastructure, with the bank revealing yesterday that the number of high impact incidents ("Severity 1" systems failures) dropped from 67 in 2013 to 44 in 2014.A robust platform is essential, given shifting customer preferences for round the clock banking. CBA revealed that, while only 21 per cent of all transactions by volume were conducted over the internet, these now amounted to the largest group by value (47 per cent of total transaction value comes from internet transactions compared to 39 per cent in branches).CBA's recently appointed CIO, David Whiteing, had a second row seat at the results announcement yesterday, but Narev made clear Whiteing has a front row task in the year ahead."By getting more productivity here we do not need to offshore Australian jobs," said Narev, who stressed the importance of effective processes and technology in terms of delivering the required productivity improvements.