Disabled Disks on a Hard Drive,What?!?

I was reading one day in Maximum PC or PC World Magazine that all hard drives made by any one particular manufacturer are all the same. the only difference is that some of the disks are disabled, so I recently bought a 1 TB external hard drive in the hopes that I could enable the "hidden" disks. If there is truly a way to do this, could someone tell how, or point me to an article that could show me? I've searched the internet with every search term I could think of. nadda.