In the OS world Operating Number 6 would appear to be a cursed number! Let's take a look shall we. Firstly let's begin with the Grandaddy! DOS. It never made it past version number 6, thanks to a new fangled Windows! It was not the only operating system to suffer under windows and Mac OS 6 was born at a time that it was dripping Market share to Windows 3. Zeta BE OS version 6 was surrounded by controversy and eventually died the death of the unknown.
About decade later and we have the most famous failure of all... Windows 6! Don't remember the name, well perhaps that's because they called it Vista. In fact it was so bad, that Apple Sales people said that they greatest sales tool they had was Vista! And finally we have iOS 6, which considering the fate of version number 6 of other operating systems isn't so bad, except when it comes to finding anything in the real world!
Still there is one consolation, Unix 6 was the first version to make it outside of Bell Labs and we can be very grateful for that, because not only did it give us Linux, but also Next, which in turn got us OS X.