The black cube computer introduced by Steve Jobs at NeXT in 1990 was the NeXTcube.
NeXT had previously released the NeXT Computer in 1988, a black workstation often nicknamed the Cube. The NeXTcube was its successor and used a distinctive magnesium-case cubic design.
The NeXTcube ran the NeXTSTEP operating system and was aimed primarily at universities, businesses and scientific users. Its hardware was technically ambitious, but NeXT’s workstation sales remained limited compared with mainstream personal computers.
NeXT’s software later became strategically important to Apple. Apple acquired NeXT in 1997, bringing Jobs back to the company and providing technology that influenced the development of Mac OS X.