$23 Quadrillion

VISA debit errors caused by spaces instead of zeroes. This illustrates the importance of testing and following a spec. [Link]

The secret of the $23 quadrillion VISA debit errors looks like a specific and not uncommon programming error. Take the insanely large number, if you convert 2314885530818450000 to hexadecimal, you end up with 20 20 20 20 20 20 12 50. In programming, hex20 is a space. Where a binary zero should have been, there were spaces instead. What made this instance special is that it wasn't caught in time.

In programming, when you allocate memory in almost all environments, the contents of the variable is not defined. It could be anything, and because of that, you need to initialize that value with something appropriate. Sometimes 20hex which is a space, sometimes 0hex which is null, sometimes numeric 0 which is actually 30hex. It all depends on what you need.

Character	Decimal (Base 10)	Hexadecimal (Base 16)
NUL	0	0
' '	32	20
0	48	30

ASCII Chart