Colossus and the Birth of Computing

Introduction

Breaking Lorenz by hand was possible but agonisingly slow. Tommy Flowers proposed a machine made of valves — thousands of them — to do the statistical tests automatically.

Colossus did not break every cipher, but it found the correct wheel settings in hours instead of weeks. Its existence stayed secret long after the war, yet it shaped every computer that followed.

Key ideaColossus was the world's first programmable electronic computer. It searched Lorenz wheel settings at valve speed.