SMART Extended Test Details

[kyebean]

I suspect that SMART tests vary in their implementations between manufacturers, I'm interested in what is common to all manufacturers.
Do SMART extended tests attempt to write every sector (backing up and replacing on the fly to avoid data destruction) or are they just read tests? If they are just read tests, do they still prompt reallocation like writing every sector does? Would they do this by reading every sector, and then if a read error is encountered they attempt to write/reallocate that sector? Thank you.

[HaQue]

It isn't only the vendors of the hard disks that can interpret and implement whatever they want, it is also every other part of the system such as Mainboards. I suggest you read the Wikipedia article especially the part "Lack of common interpretation" and with statements like:

From a legal perspective, the term "S.M.A.R.T." refers only to a signaling method between internal disk drive electromechanical sensors and the host computer. Hence, a drive may be claimed by its manufacturers to implement S.M.A.R.T. even if it does not include, say, a temperature sensor, which the customer might reasonably expect to be present. Moreover, in the most extreme case, a disk manufacturer could, in theory, produce a drive which includes a sensor for just one physical attribute, and then legally advertise the product as "S.M.A.R.T. compatible"

If you are looking for any resemblance of standardisation, then I don't think you are going to have much success.

[kyebean]

That's what I feared. In that case, I'm hoping someone has enough experience/knowledge to answer my question(s) in regards to the way the extended test is most commonly implemented.