Burroughs B7700

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 Robert (Bob) Barton 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 12-bit instructions and 48-bit data words. The first such design was the B5000 in 1961. It was optimized for running ALGOL 60 extremely well, using simple compilers. It evolved into the B5500. Subsequent major redesigns include the B6500 line and its successors, and the separate B8500 line. 'Burroughs Large Systems' referred to all of these product lines together, in contrast to the COBOL-optimized Medium Systems or the flexible-architecture Small Systems.