Linux Kernel (1991) 4 Linux

Linux, originally created by the Finnish programmer Linus Torvalds, is a Unix-like operating system loosely inspired by Minix. The pivotal difference, however, was how it was licensed. Unlike Unix operating systems that remained expensive and proprietary, Linux and its source code were licensed for free distribution, with the provision that all changes or additions to the source code must also be released for free.

• 0.x

Netscape (1994) 72 Web Browser Windows OS2 Unix Linux MacOS Other

Netscape Navigator/Communicator was the first commercial web browser, displacing the free NCSA Mosaic. 1.0 was first released in December 1994, and initially offered advanced features such as progressively rendering pages as they loaded. It quickly gained many other features and capabilities and became the most popular web browser in the mid 1990s. One reason for its popularity, it was licensed freely for personal and non-profit use, although companies were expected to pay for a license. It later competed with Microsoft Internet Explorer, Opera, and Safari, and eventually was open sourced in to the Mozilla browser.

• 3.0.x

Xenix (1984) 17 Linux

Xenix was the variant of UNIX originally published by Microsoft, later sold to SCO. It added a variety of technical enhancements over System V Unix, including a menu-driven business shell. It was ported to many different platforms from a PDP-11 including the Altos 8600 (First x86 port), IBM PC, Intel System 86, TRS-80 Model 16, SCP Gazelle II, and Apple Lisa. The Xenix Software Development System, Microsoft Multiplan 2.x and Microsoft Multiplan 3.x, Microsoft Word 3.0 and Microsoft Word 5.x, and FoxBase Plus 1.00

• IBM PC 2.00