The Best-Known Program Errors of All Time

At the beginning of September, the whole world celebrated tester’s day and day of bug. That is why we prepared some interesting facts about the biggest system errors and bugs in history that people discuss for a long time.

A Real Bug

Undoubtedly, the top position in our list goes to a situation that happened on the 9th of September, 1947. That day a group from Harvard University tested the performance of the Mark 2 Aiken Relay electromechanical computer and found a bug that was trapped between two contacts of a relay. This caused a short circuit and, as a result, led to the malfunctioning of the whole programmed machine.

The bug was carefully removed out of the system and taped to the technical journal of the university. Under the bug remains, there was a sign: “The first case of a bug detection”. By the way, since that, all the system errors in any programmed software performance began to name bugs.

Y2K Problem

A Y2K glitch is also known as the Year 2000 problem. Software developers in the XX century tend to use the last two numbers of a year to identify it instead of mentioning all four of them.

Such a format of data saving was very effective. Firstly, every byte counted, and the database could save up to a thousand dates at the same time. In this case, shortening is a good practice, isn’t it?

On the 1st of January, 2000, some big cities have faced power interruptions, breaks in water-supply systems, and malfunctioning of other benefits of civilization. This happened due to the shortening of the format of the year. Since the beginning of 2000, machines interpreted this year as 1900. And at a moment’s notice, a lot of systems stopped working all over the world.

AT&T Phone System Breakdown

One of the public exchanges of the AT&T phone network has been broken. Nevertheless, it was able to transmit data to other switch units. But the problem was that the information was incorrect and it disabled this operator for 9 hours. Thus, more than 60 thousand people couldn’t make a phone call.

A cause of the bug was the last software update for the telephone switching system. If one of the exchanges goes down, it “tells” other units to intercept its traffic. The rest switch units have to be updated to new functional modes from time to time and check if the first one performs properly.

But due to the defect in the program code, the broken exchanger has sent two messages. The second one was delivered during rebooting. That is why exchangers thought that they’re broken and have sent messages to new switch units.

A Failure of an Ariane 5 Launch Vehicle

In 1996, there was an incident with the Ariane 5 rocket vehicle. Just after 40 seconds after initiation, the launcher broke up due to the incorrect performance of the flight software. This error is the most expensive failure worldwide as of now. Its damage amounted to 360 – 550 million dollars.

The problem was that some software elements for the new rocket were taken from its previous version. But specialists didn’t test the system and its new function properly. Some functions couldn’t overlay each other correctly. Hence, it causes the failure of the rocket that was built and developed for about 10 years.

Microsoft Bob

For some time, there was an operating system called Microsoft Bob – a system with a minimal graphical interface. It was a small virtual house with simple rooms: a kitchen and guest rooms.

The objects placed in it exactly corresponded to the functions that they could perform. For example, pen and paper opened up a graphics editor.

But there were problems with the security system. If a user was unable to log in 3 consecutive times, the software asked him if he had forgotten his password.

If the client answered positively, the system let him in the system and asked to create a new password. That is, anyone could access another person’s local machine.

By the way, according to the CNE.com portal, this OS has become the worst product in a decade.

Free for Everyone

In the early days of the Amazon marketplace empire, users could easily order negative amounts of products on the site. The money for the purchase was not debited, but on the contrary, was transferred to the user’s card. This problem arose due to the frequent release of new versions of software that weren’t tested.

Similar elementary bugs are often found in other Internet resources. Thus, for example, some marketplaces could store user data in cookie files. This meant that hackers could make purchases on other people’s behalf by simply editing the customer ID.