However, it was clear even then that while there may be some shared elements between OS X and this new phone OS, it was a different-enough beast to warrant its own branding.
When the original i Phone launched, the OS was called "i Phone OS" and it kept that name for four years, only changing to i OS with the release of i OS 4 in June of 2010.
For the sake of simplicity (and because it's a much-less awkward phrase), I'm going to indulge in a little revisionist history here and refer to all versions of the operating system as "i OS" in this piece.
Although it may be difficult to imagine now, when the original i Phone was introduced, it was actually well behind the competition when it came to a strict feature-by-feature comparison.
Through what can only be described as relentless and consistent improvement over the years, Apple has made i OS one of the most feature-rich and well-supported platforms on the market.