In 1964, IBM risked its entire corporate empire on the System/360, a chaotic gamble to make all of its future machines compatible with the same software — and the architecture proved so robust that modern enterprise mainframes today are still running sections of binary code written more than sixty years ago – Make Tech Easier

On the morning of April 7, 1964, in a coordinated announcement broadcast to more than 100,000 people gathered in 165 cities around the world, IBM did something almost no large company had ever done.

It bet itself.

The product it was unveiling was called the System/360 — a family of six computers, fifty-four peripherals, and a new operating system, all designed to do something no computer family had ever done before. They would all be compatible. Software written for the smallest, cheapest model would run, without modification, on the largest, most expensive one. Customers who outgrew their machine could simply buy a bigger one and keep their existing programs.

It sounds obvious now. In 1964, it was revolutionary. And IBM had spent so much money trying to build it — roughly $5 billion, more than was spent on the Manhattan Project — that if it failed, the company would not survive.

The gamble paid off. The System/360 became the most successful computer family in history. And…