I think everyone (well, most people) realize that manufacturer's like to use decimal (base 10) when describing their drives, but the computer bases the volume on binary (base 2). And Makoto did a good job of explaining the difference in the first post.
But I too found the article odd - in fact, I highlighted the comment so I could ask about it here (yes, I highlight my mag - what's wrong with that?!)
Josh Norem wrote:
We tested the 240GB version of the drive, which is 223GB after being formatted. The extra 16GB of space you can't see or access is used for over-provisioning.
Midrange SSD Mayhem, Maximum PC, March 2013, p. 78
Over-provisioning is NOT the difference between decimal and binary. For those that don't know, over-provisioning is hidden storage the SSD uses to perform administrative tasks, like TRIM. The user should not see this space.
So I'm torn: I lean towards agreeing with Makoto that this is a decimal v. binary difference, but Josh states otherwise. Is it possible it is a true 240GB drive with a 16-ish GB hidden sector? Perhaps the author of the article could confirm. Josh...?