Pentium FP Bugs
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Study Guide

What is the Intel Floating-Point Bug?

Intel Pentium chips manufactured with a clock speed of less that 120 MHz is possibly susceptible to this bug. The bug can be seen in floating point division and can approach a magnitude of 61 parts per million.

How was the Intel Bug Found?

Dr. Dr. Thomas R. Nicely was pursuing a research project in an area of pure mathematics called computational number theory. In June of 1994, a number of results were processed, and the results did not agree with published values. This led to a long search for logic errors and sources of reduced precision in the source code. Nicely reproduced the error in many programs and languages to determine if the particular code he was using was not compatible with Intel's chip. He also checked different Pentium chips from different manufacturing plants to determine if the bug was localized to a particular factor. All the chips failed, leading Nicely to determine the cause of the error to be the Pentium chip. Intel had already discovered the error at this point, but decided to keep quiet in an attempt to sweep the problem under the rug.

Impact of the Intel Bug

The erroneous Pentium processor caused many individuals to worry about the correctness of the calculations using the processor. Many scientific applications require precision from calculations. One example is Mathworks, the creators of MATLAB, a mathematics calculator that guarantees correct mathematics. Mathworks had to rewrite much of the Matlab software to insure that the processor would not produce incorrect results. Many professionals were scared to use the processor and the much of the Intel business shifted to PowerPC. This bug also created a safety hazard for all people that were affected by the faulty calculations. Computers are used in the creation of every man made item. Even small miscalculations could prove deadly in the creation of bridges, structure, and medicine.

Responsibility of Intel

In late 1994, almost a half-year since the internal discovery of the bug, Intel took steps to address the problem. They stated that the errors would not affect most users and stated the probability of an error was 1 in 27 million. Intel quickly fixed the bug on all new chips, but did not offer any plan for replacing the original bugged chips. Instead Intel went on quietly trying to devise a software solution. It seemed as though Intel was not going to fix the problem. The beginning of a class action lawsuit changed Intel's outlook on the problem. They offered a full return policy to fix flawed processors. This small oversight cost the company over 475 million. The main reason that Intel withheld the bug was an attempt to save money. This action was entirely unethical, they put the bottom line in front of the consumer and sold a fraud of a product.

Ethical Issues

Intel let the problem manifest for 6 months after their own internal discovery of the problem. The company violated many of the code of ethics that engineers from all branches adhere to. First and foremost any product offered to the public comes with a guarantee to be free from design error. If such an error becomes apparent by its users, the company that issued the product must take the proper steps to insure the problem is fixed. Intel let the bottom line come between the company and its ethics. Intel made a grave decision in part do to a lack of ethics by the decision makers as well as the workers that discoverd the bug. It is not enough to fix the problem on all new models. The company should have had leadership that was bright enough to realize the ethical issues and make the right decisions.

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