Testing horror stories

Over time, there have been many incidences where testing has gone terribly wrong! Let’s explore some of the most well known horror stories.

Panel F, Relay 70 of the Harvard Mark II system (1945)

On September 9, 1945, a Harvard technical team looked at Panel F and found something unusual between points in Relay 70. It was a moth, which they promptly removed and taped in the logbook. Grace Hopper added the caption "First actual case of bug being found". This is the first time anyone used the word bug to describe a computer glitch! Naturally, the term debugging followed.

Therac-25 Medical Accelerator (1985-1987)

The Therac-25 Medical Accelerator was built for radiation therapy by the AECL and CGR in France. Unfortunately, the Operation System was designed and planned by an under-experienced programmer. The power of the electron beam reached too high a power, leading to the death of five patients and permanently injuring every other patient.

Ariane 5 Flight 501 (1996)

Working code for the Ariane 4 rocket is reused in the Ariane 5, but the Ariane 5's faster engines trigger a bug in an arithmetic routine inside the rocket's flight computer. The error is in the code that converts a 64-bit floating-point number to a 16-bit signed integer. The faster engines cause the 64-bit numbers to be larger in the Ariane 5 than in the Ariane 4, triggering an overflow condition that results in the flight computer crashing.

NBN Services (2019)

All NBN (National Broadband Network) Co satellite broadband services delivered by IPstar went offline on the 25th January 2019, after what appears to be a core network equipment failure. The outage affected around 12,000 fixed wireless services in South Australia.

The CBA Payroll Migration (2019)

The Commonwealth Bank of Australia has celebrated the first anniversary of its new cloud-based ADP payroll system with Workday integration by promising employees to deposit back pay from underpayments that occurred in previous years. They will roll this out as soon as next week as a major accounting clean-up continues. While the new payroll, which replaced CBA's ageing Peoplesoft clunker in March last year, is working fine, Australia’s largest institution has confirmed the payment and entitlements mistake were uncovered in a review of the payroll system during preparations for the mass migration for 50,000 staff.

The Future (Unix 2038)

Not all computers handle dates in the same way, and many computers based on the UNIX operating system handle dates by counting how many seconds a date is since 01/01/1970. For example, the date 01/01/1980 is 315,532,800 seconds after 01/01/1970. This number is stored on these computers as a “signed 32-bit integer”, which has a size limit of 2147483647.

That basically means it can only handle dates that are up to 2147483647 seconds after 01/01/1970 – which only takes us up to the 19th of January 2038, after which, we may have problems again.

This is especially true when we consider that UNIX-based software is more commonly used in “embedded systems” rather than a home PC – that is, systems that have a very specific purpose closely related to their hardware, such as software for robotic assembly lines, digital clocks, network routers, security systems and so on.

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