On Tue, 24 Apr 2018, Michael Kjörling wrote:

[ ... ]

> That's definitely statistically significantly slower toward the outer 
> edge of the disk as presented by the OS. That _should_ translate to 
> slower for higher LBAs, but with all the magic happening in modern 
> systems, you might never know...

Exactly; with disks these days it's pointless trying to second-guess 
what's happening under the bonnet (ObUS: hood).

A well-known question in the security field, for instance, is how do you 
know that you have *really* erased that disk?  The thing can lie as much 
as it likes, and you'll never know for sure.

-- 
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."