what is OS8

Best guesses are:

a) Mac OS X 10.8 (Mountain Lion) which is something that could be running on your Mac mini.

b) iOS 8, which is the current iPhone/iPad/iPod Touch operating system.

c) very unlikely you are talking about Mac OS 8 (no 'X' in the name), which is a version from the '90's in the Mac Classic generation of operating systems.

I think you are inquiring about OSX 10.8.x which is the Mountain Lion version of the System. You can buy it from App Store.

Before you do, check out any Apps that you currently have; many of them will be Rosetta based and will not work with this OS. And of course, you will need to know if your machine will support Mountain Lion.

Tell us if this answers your basic question and we will try to guide you if you want to upgrade.

A very old, now defunct, operating system that came long before OS X.

It cannot run old any Intel based Macs.

OP shows as using OS 8.6 or earlier.

Not on a Mac Mini from 2007 he's not. Something doesn't fit with that profile

True, but difficult to guess which part of his signature is correct!