Software developers spend between 50 % and 70 % of the time testing and validating code Despite this, reliability is still the main problem of software products (e.g. Microsoft Windows) A recent study estimates the cost of bad software for industry in 60 billion dollars per year The cost of a software bug in a critical system can be of millions or even billions 2 Ariane 5 crash (1996) The launcher began to disintegrate at about 39 seconds because of high aerodynamic loads resulting from an angle of attack of more than 20 degrees. 3 The cause The angle of attack was caused by incorrect altitude data following a software exception. The software exception was raised by an overflow in the conversion of a 64-bit floating-point number to a 16-bit signed integer value. The result was an operand error. The operand error occurred because of an unexpected high value of the horizontal velocity sensed by the platform. The value of BH was much higher than expected because the early part of the trajectory of Ariane 5 differs from that of Ariane 4 and results in higher horizontal velocity values.

Software developers spend between 50 % and 70 % of the time testing and validating code Despite this, reliability is still the main problem of software products (e.g. Microsoft Windows) A recent study estimates the cost of bad software for industry in 60 billion dollars per year The cost of a software bug in a critical system can be of millions or even billions 2 Ariane 5 crash (1996) The cause The angle of attack was caused by incorrect altitude data following a software exception. The software exception was raised by an overflow in the conversion of a 64-bit floating-point number to a 16-bit signed integer value. The result was an operand error. The launcher began to disintegrate at about 39 seconds because of high aerodynamic loads resulting from an angle of attack of more than 20 degrees. The operand error occurred because of an unexpected high value of the horizontal velocity sensed by the platform. The value of BH was much higher than expected because the early part of the trajectory of Ariane 5 differs from that of Ariane 4 and results in higher horizontal velocity values. 3 4 Loss of Mars Climate Orbiter (1999) Direct cost 500.000.000 EUR, indirect cost 2.000.000.000 EUR To know more:

Software developers spend between 50 % and 70 % of the time testing and validating code Despite this, reliability is still the main problem of software products (e.g. Microsoft Windows) A recent study estimates the cost of bad software for industry in 60 billion dollars per year The cost of a software bug in a critical system can be of millions or even billions 2 Ariane 5 crash (1996) The cause The angle of attack was caused by incorrect altitude data following a software exception. The software exception was raised by an overflow in the conversion of a 64-bit floating-point number to a 16-bit signed integer value. The result was an operand error. The launcher began to disintegrate at about 39 seconds because of high aerodynamic loads resulting from an angle of attack of more than 20 degrees. The operand error occurred because of an unexpected high value of the horizontal velocity sensed by the platform. The value of BH was much higher than expected because the early part of the trajectory of Ariane 5 differs from that of Ariane 4 and results in higher horizontal velocity values.

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