Doug Wilson/CORBIS/Corbis via Getty Images Follow ZDNET: Add us as a preferred source on Google. ZDNET's key takeaways Microsoft open-sourced the MS-BASIC language. Bill Gates would never have seen this coming back in the day. MS-BASIC 1.1 was many developers' first language. If, like my ZDNET colleague David Gerwitz and I, you were tinkering with computers in 1975, you badly wanted an MITS Altair 8080 computer, the first PC. To build software on it, most of us used Altair BASIC. A pair of college dropouts named Bill Gates and Paul Allen wrote the language. Then they formed a company, Micro-Soft, to sell it. You know that company better as Microsoft. Also: Microsoft at 50: Its incredible rise, 15 lost years, and stunning comeback - in 4 charts In 1976, they rebranded Altair BASIC to Microsoft BASIC 1.1 and ported it from the 8080 processor to the MOS 6502 microprocessor. Gates had always intended this BASIC to run on more than just the Altair PCs. As he said in a Smithsonian interview, "MITS was only one company, and we wanted our software to be used on all the machines." It was a great move. MS-BASIC became a wildfire success. That's because it was the first high-level language for many of the early PCs, such as the Apple II, Commodore PET, VIC-20, and one of the first important gaming platforms, the Nintendo Entertainment System. Now, the ancient 6502 assembly code language has been open-sourced under the MIT License. The Bill Gates of 1976 would have been shocked to see this. He hated the idea of people using MS-BASIC for free. In a widely distributed letter, Gates wrote, "Most of you steal your software. Hardware must be paid for, but software is something to share. Who cares if the people who worked on it get paid?" That went over like a lead balloon. You may wonder why. Didn't we always have to pay for programs? Actually, no, we didn't. Software was usually shipped with hardware. When you did get a program, you'd get the code and then need to type it into your computer. Yes, it was a pain. Floppy disks? Cassette tapes? Luxury! Pure luxury! If they were lucky, people using mainframes and mini-computers got programs on 9-track tape. Also: The most popular programming languages (and what that even means) It wasn't until 1976 that you could copyright software. This change to copyright law and the related court decisions, such as the antitrust suit that forced IBM to unbundle hardware and software, are what made proprietary software possible. That was almost 50 years ago; since then, Microsoft has embraced open-source software. In recent years, Microsoft has started releasing some of its classic operating systems and programs as open source. These include: MS-DOS 4.0; GW-BASIC, Microsoft's 1983 BASIC interpreter for IBM PC compatibles; and Windows Calculator. For its day, MS-BASIC 1.1 was quite sophisticated. It included improved garbage collection. (When you only had 4K of RAM, you needed every byte your program could get its hands on.) It also supported FOR loop variables, which were a big improvement over BASIC's infamous GOTO command. Also: BASIC turns 60: Why simplicity was this programming language's blessing and its curse Microsoft BASIC 1.1 also included core language elements such as integer and floating-point arithmetic, string support, robust statement handling, and memory management. Not bad for a language written in 6,955 lines of 6502 assembly language code. Today, it lives on as Visual Basic, which remains a supported language for Windows application development. In its day, MS-BASIC 1.1 introduced programming to a generation. It gave many developers their first taste of coding. The language also, of course, provided the foundation for Microsoft's first business model of licensing software to hardware companies and individuals.