ABC meaning in Computer Hardware ?

The Atanasoff–Berry computer (ABC) was the first automatic electronic digital computer. Limited by the technology of the day, and execution, the device has remained somewhat obscure. The ABC's priority is debated among historians of computer technology, because it was neither programmable, nor Turing-complete. Conventionally, the ABC would be considered the first electronic ALU (Arithmetic Logic Unit) - which is integrated into every modern processor's design.

Its unique contribution was to make computing faster by being the first to use vacuum tubes to do the arithmetic calculations, which ultimately culminated with Jon von Neumann designing the ENIAC with vacuum tubes instead of using slower electro-mechanical methods used by the Harvard Mark I, and Konrad Zuse's machines (which were programmable, but slow). The first electronic, programmable, digital machine, the Colossus computer from 1941 to 1945, used similar tube-based technology as ABC.