What is the difference between FAILING and FAILED?

The FAILING status is SMART Utility's pre-fail algorithm warning about a drive that may fail in the future. The FAILED status is the drive's internal algorithm warning about a drive that will fail in the future. Volitans Software devised the pre-fail algorithm, while the drive's internal algorithm was devised by the drive's manufacturer.
<- Does having just a few bad sectors actually mean my drive is failing? What is the difference between the threshold, worst, value, and raw numbers in the attributes window? And why do some attributes show a very high value (like 426900000)? ->