The computing pioneer Maurice Wilkes famously described his 1949 encounter with debugging like this: "As soon as we started programming, [...] we found to our surprise that it wasn't as easy to get programs right as we had thought it would be. [...] Debugging had to be discovered. I can remember the exact instant [...] when I realized that a large part of my life from then on was going to be spent in finding mistakes in my own programs."37
Seven decades later, modern computers are approximately one million times faster and also have one million times more memory than Wilkes's Electronic Delay Storage Automatic Calculator, or EDSAC, an early stored-program computer using mercury delay lines. However, in terms of bugs and debugging not much has changed. As developers, we still regularly make mistakes in our programs and spend a large part of our development effort trying to fix them.