5 most awful tech failure across the world

Patriot Missile Failure

Cost: 28 Soldiers dead and 100 people injured.

In 1991, during the Gulf War an American Patriot Missile battery in Dhahran, Saudi Arabia, failed to track the incoming missile from Iraqi Scud. The missile struck on American barracks that cause of killing 28 soldiers and injuring around 100 people. In one report is found that Software problem lead to system failure at Dhahran.  It turns out that the reason was wrong calculation of the time since boot due to computer errors. Specifically, the time in 10^th of second as measured by the system’s clock was multiplied by 1/10 to produce the time in seconds. This calculation was performed by 24 bit fixed point register. In particular, the value 1/10, which has a continuous binary expansion, was sliced at 24 bits after the radix point. The small slicing error when multiplied by the bigger number giving the time in tenths of a second which led to big system error. Indeed, the Patriot battery had been up around 100 hours, and an easy calculation shows that the resulting time error due to the large chopping error was about 0.34 seconds.

A Scud travels at about 1700 meters per second, and so in this time travels more than 1/2 kilometer. This was enough that the incoming Scud was outside the range gate that the Patriot tracked. Ironically, the fact that wrong time calculation had been improved in program code, but not all, contributed to the problem, since it meant that the inaccuracies did not cancel.

Y2K

Cost: $500 million.

Y2K problem is also known name year to problem, Y2K bug. It was a programming mistake made by programmer represent the four digit year with only the final two digits. That cause the year from 1900 to 2000 is indistinguishable. Until the 1990 many computer programs were designed to stands 4 digit year as 2 digits in order to save memory space. These types of computers could recognize ‘97’ as ‘1997’ but would be not able to recognize ‘00’ as ‘2000’, perhaps interpreting it to mean 1900. But when the clocks struck midnight on January 1, 2000, many affected computers would be using incorrect date and thus failed to operate properly still the computers software was replaced before that date. In addition many computers software did not take into account that the 2000 was a leap year. Early programmers often used a series of 9s to indicate the end of a program so dawn of 2000, it was feared that some computers might fail on September 9, 1999 (9/9/99).

Such a misreading would lead to software and hardware failures in computers used in important areas likes banking, government records, and so on, with the potential to widespread chaos on and following January 1, 2000. Y2K problem was much dangerous mainframe computer including those typically used to run insurance companies and banks even newer systems that used networks of desktop computers were considered critical.

The Pentium Problem

Cost: $475 million.

Most popular microprocessor Intel Pentium was coming in market in 1994 was carrying a bug in floating point unit. There were around 5 million defected chips in market and Intel eventually decided to replace all the chips for anyone who face the problem and complained. Later, Intel turned some of their faulty processors into key chains. Many software packages, including many that do use floating-point numbers, did not use a computer's FPU. These packages did not show any error, also only certain numbers divide incorrectly. Consequently many users may never recognize the division error. The most popular example is 4195835/3145727, discovered by Tim Coe of Vitesse Semiconductors. The correct value is 1.33382 to 6 sig. figs, while the flawed Pentium's floating-point unit computed 1.33374 to 6 sig figs, a relative error of 0.006%.

Intel publicly announced that an error is only likely to occur once in nine billion random floating point divides.  Critics noticed that while hitting a pair of bad inputs then the Pentium's output for those inputs was wrong every time. Within a month IBM halted shipment on Pentium based computers and announced that the Common spreadsheet programs are recalculating for 15 minutes a day, could produce Pentium related errors as often as once every 24 days.

Cluster II           

Cost: $370 million.

Cluster Spacecraft is space mission of the European Space agency with NASA participation to study the Earth’s magnetosphere over the course of nearly two solar cycles. The mission was composed the four identical spacecraft. The spacecraft are cylindrical and spinning at 15 times rotations per minute. After launched, their solar cells provided 224 watts power to instruments and communications. Solar array power has gradually declined with the mission progressed due to damage by energetic charged particles All spacecraft maneuver into various tetrahedral formations to study the magnetospheric structures and boundaries. The inter spacecraft distances had varied from around 4 to 10000 km.

All is right until the whole system terminated when a computer program tried to change the sideways rocket velocity from 64-bit to 16-bit format. The number was too large, caused the inadequate protection from integer overflow. When the guidance software shut down, control passed to an identical redundant unit but that also turned into a failure because it was also running on the same algorithm. As a result flight was diverted from its original path after launch of 37 seconds. Finally, the rocket self destroyed itself by its automated flight termination system.

Mars Climate Orbiter

cost: $125 million.

The Mars Climate Orbiter was a robotic space probe launched by NASA on December 11, 1998 that was 338 kg to know the Climate and atmosphere of mars and to act as the communications relay in the Mars Surveyor 98 program for Mars Polar Lander. On September 1999 the connection was lost with the spacecraft as the spacecraft went into orbital insertion due to the ground base computer software, which produced output in non SI units of pound-seconds instead of the SI units of Newton seconds.

The Mars Climate Orbiter bus measured 2.1 meters high, 1.6 meters wide and 2 meters in depth and the internal structure was largely constructed with graphite composite aluminum honeycomb supports that found in many commercial airplanes. And all scientific instruments likes battery and main engine, the spacecraft included dual redundancy on the most important systems. The spacecraft has 1.3-meter high-gain antenna to receive data with Deep Space Network over the x-band. The radio transponder designed for the Cassini Huygens mission. It also included a two way UHF RF system to relay communicate with Mars Polar Lander depends upon an expected landing on December 1999.