The IBM 5150 Personal Computer, unveiled on August 12, 1981, was not the first personal computer to be invented, neither was it the most powerful. However, it is widely heralded as the machine that ignited a home computing revolution.

If you’re reading this article on the touchscreen computer you carry around in your pocket, its lineage can be traced all the way back to the 5150.

From the typewriter to the computer

Throughout the middle decades of the 20th century, International Business Machines (IBM) forged its name by pioneering electro-mechanical typewriters.

IBM Model 01

Machines like the 1935 IBM Model 01 Electromatic Typewriter allowed lighter keystrokes and less reaching.  They would evolve into the Mag Card Selectric word-processors of the 1970s. These devices could store information for reprinting and even undo mistakes thanks to correction tape.

[Related story: The evolution of the typewriter]

While its typewriters led the market, IBM was also dabbling in the next step: personal computers. The IBM 5100 Portable Computer (below) was revealed back in 1975, but priced $11,000-$20,000 (£7,000-£12,900) and weighing 50lb, it was hardly a market-ready, consumer solution.

By later that decade things were beginning to change. Forged by hobbyists, the market was starting to grow thanks to devices like the now-legendary Apple I, as well as computers from Commodore and Tandy.

 IBM 5100 computer

As IBM prided itself on building all of its components in house, the pervading thought was the company couldn’t build its own riposte quick enough to match the competition.

"IBM bringing out a personal computer would be like teaching an elephant to tap dance,” one analyst wrote.

Even internally, there were doubts. IBM had initially concluded there weren’t enough applications for personal computers to be widely adopted in the office or the home.

IBM develops the Personal Computer

Once it had decided to take the plunge, the key was to break from tradition and build a machine with off-the-shelf components, like the 4.77Mhz Intel 8088 processor.  As such IBM was able to develop the 5150 within a year from its HQ in Boca Raton, Florida. That’s about as far away from Silicon Valley as it’s possible to be.

Crucially, the IBM 5150 contained a brand new operating system called MS-DOS (Intel called it PC-DOS).

It was built, at Intel’s behest, by a programming start-up called Microsoft. Of course MS-DOS would become Windows once a graphical user interface (GUI) was placed on top in years to come.

Woman using IBM 5150 Personal Computer

"This is the computer for just about everyone who has ever wanted a personal system at the office, on the university campus or at home," Intel claimed upon launch.

"We believe its performance, reliability and ease of use make it the most advanced, affordable personal computer in the marketplace."

The floppy disk-based 5150, priced at $1565 (just over £1,000), was a huge success and sold 200,000 within the first year.

IBM’s pitching of the 5150 as machine that anyone could use, rather than something to be pieced together and mastered by gadgeteer, was crucial, as you can see in the advert below.  It had created an appetite for computers in the office and the home.

Also, while Apple computers were still considered toys for hobbyists, IBM had almost half a century’s experience in creating trusted machines for businesses. As thus, the 5150 was a revelation.

“The speed and extent to which IBM has been successful has surprised many people, including IBM itself," wrote the New York Times.


The legacy of the IBM Personal Computer

Amid its success, the IBM 5150 shaped the modern computing industry in many different ways.

The decision to use components from other manufacturers, rather than build everything in house, remains the pervading model in the computing industry. A phone might feature a camera sensor built by Sony, a processor manufactured by Samsung and a screen made by LG, among others.

Back then the thinking was foreign, but it allowed the strongest innovations from a myriad of different companies to be pieced together to build a much more effective machine.

[Related story: 8 computers that changed the world]

This also gave rise to other manufacturers who could now assemble as system from existing parts, rather than build everything from scratch.

IBMs choice to eschew an all-in-one solution for cable-connected monitors and keyboards created the design framework for the desktop PC, which would endure unchallenged until the all-in-one iMacs of the late-90s.

Perhaps most importantly, it helped to establish Microsoft as an important player in those early days of personal computing. We all know how that panned out.

For a couple of years, IBM would own the burgeoning home PC market and would not have any competition until Apple launched the first Macintosh in January 1984.

The Mac vs PC era was born.

Do you remember the IBM 5150 Personal Computer? Let us know in the Comments section below.