“Is this acceptable? Not really. Is it understandable? Absolutely.”

When you visit parts of the website of the Driver & Vehicle Licensing Agency in the U.K. outside of standard office hours, you will see this:

It seems ridiculous, almost like the famous 500-mile email bug, but Dafydd Vaughan explains how it came to be. It won’t be a surprise that the story starts with an old computer system, built around a day/night cadence where people would visit the agency during the day, the information would be collected, and all the data processing would happen overnight:

At the time, many of DVLA’s services – particularly those relating to driving licences were still backed by an old IBM mainframe from the 1980s – fondly known as Drivers-90 (or D90 for short). D90 was your typical mainframe – code written in COBOL using the ADABAS database package. Most data proc…