Decades before Windows 8.1 and Office 365 hit the market, MS-DOS and Word for Windows graced the hulking, low-resolution CRT monitors of ’80s-era PC users. Now, Microsoft is finally letting the public peek into the code that made those two early software offerings tick and helped set the stage for one of the IT industry’s biggest success stories.
“On Tuesday, we dusted off the source code for early versions of MS-DOS and Word for Windows,” said Roy Levin, distinguished engineer and managing director of Microsoft Research, in a March 25 statement. Working with the Computer History Museum, “we are making this code available to the public for the first time,” he announced.
While based on a command line interface, MS-DOS, or the Microsoft Disk Operating System, which began shipping on IBM PCs in 1981, provided a foundation for the software giant’s trademark Windows operating system. Early versions of Windows were essentially a graphical user interface overlaid on MS-DOS.
Compared with today’s pixel-packed mobile touch-screens and visually slick operating systems, MS-DOS is a barebones computing experience. In an article on the software’s contributions to computing, Len Shustek, chairman of the board of trustees of the Computer History Museum, described MS-DOS as “basically a file manager and a simple program loader. The user interface was text commands typed on a keyboard, followed by text responses displayed on the screen. There was no graphical output, and no mouse for input.”
Despite its age, Word for Windows hews closer to modern user interfaces. It’s successor, the DOS-based, mouse-enabled version or Microsoft Word launched in 1983. In 1989, the company would release Word for Windows, which “became a blockbuster for the company and within four years it was generating over half the revenue of the worldwide word-processing market,” said Levin.
Both MS-DOS and Word for Windows helped Microsoft become one of the largest, most lucrative tech companies on the planet. “It’s mind-boggling to think of the growth from those days when Microsoft had under 100 employees and a Microsoft product (MS-DOS) had less than 300KB (yes, kilobytes) of source code,” wrote Levin. Fast forward to today, and Microsoft has “become a company that has sold more than 200 million licenses of Windows 8 and has over 1 billion people using Microsoft Office.”
Releasing the source code is his company’s way of supporting the Computer History Museum’s efforts to spotlight big advancements in software. “As part of this ongoing project, the museum will make available two of the most widely used software programs of the 1980s, MS DOS 1.1 and 2.0 and Microsoft Word for Windows 1.1a, to help future generations of technologists better understand the roots of personal computing,” stated Levin.