RT @IBM: The IBM 5150 turns 40 years old today. 🎂

It wasn’t the first personal computer. Nor was it the most advanced. But shortly after the IBM ® Personal Computer arrived in 1981, it became the leading platform in the revolution that brought computing out of the glass house and into daily life.

But it almost didn’t happen. When the concept first came up at IBM corporate headquarters, a senior executive asked the simple question: “Why would anyone want to take a computer home with them?”

In the late 1970s, when the office closed, you turned off your terminal—if you had one—and went home. If you had work to finish up in the evening, you carried a briefcase filled with papers. You had a pencil or a typewriter to work with, and if you didn’t know how to spell a word, you used a dictionary. Back then, you were the app.

A handful of aggressive young companies set out to take computing out of back offices and give it to the people. Commodore, Apple, Tandy, Atari and Digital Research had been putting together the pieces that make up a personal computer: a microprocessor (a central processing unit on a single chip), a BIOS (the system boot code), read-only memory (usually a solid-state ROM for controlling the PC), a floppy disk drive, a motherboard and an operating system …