In the 1970s, Burroughs Corporation was organized into three divisions with very different product line architectures for high-end, mid-range, and entry-level business computer systems. Each division's product line grew from a different concept for how to optimize a computer's instruction set for particular programming languages. The Burroughs Large Systems Group designed large mainframes using stack machine instruction sets with dense syllables[NB 1] and 48-bit data words.