AN OLD adage from the early days of computing ran along the lines of “rubbish in, rubbish out”. In other words, the quality of what a computer produced was based to a very great extent on the quality of the information it was given to process.

The early applications of computer processing to business were at times tentative. In those days, machines could perform numerous repetitive tasks quickly.

Nowadays, we live and work in a very different computer-aided society. Some mobile phone manufacturers, for example, say that the processing power in their handsets is greater than that in the command module of the Apollo moon ships. So, new systems are more sophisticated, offer far superior operating speeds and a capacity to drive businesses forward with greater efficiency and competitiveness – most of the time.

Last week, we were given a reminder of the fallibility of these advanced systems when a glitch struck a business at the very forefront of logistics technology.

Like many successful businesses, Tesco uses computers in nearly every aspect of its operations. The sheer scale and complexity of its need toŠ move the right quantities of the right (often perishable) goods to the right place at the right time demands leading-edge technology that works;Š leading-edge technology that is given the right information to process.

One day last week, something somewhere went wrong – with fascinating results. An error in a drinks promotion saw the retail giant forced to call in security staff after shoppers raced to cash in.

It was reported that customers up and down the country were able to walk away with 24 cans or bottles of leading lager for only £4. The promotion was supposed to offer a saving of £4 on two cases of 12 drinks which would normally sell for £20.

Considering how many lines sit on the shelves in the average Tesco store, and how many prices have to be programmed into their systems, it may not seem such a huge glitch. But it was computer power of another sort that saw the situation worsen.

In the space of just two hours, an internet site detailing what was happening at Tesco check-outs was viewed 20,000 times, and social networking sites played their part in spreading the word about cheap beer.

A lesson for any business relying on computers.