Conventional magnetic recording places magnetic domains longitudinally, meaning the domains lie end to end on the disk. This not only limits the density of the domains, but also helps to enable the superparamagnetic effect. Long ago it was realized that if one could place the domains perpendicular to the media (also called a vertical recording), the density could be increased, as could the resistance of the domains to the superparamagnetic effect. Although the concept was easy to understand, actually implementing it has been difficult.