Internet Explorer for UNIX is a discontinued version of the Internet Explorer graphical web browser that was available free of charge and produced by Microsoft for use in the X Window System on Solaris or HP-UX. Development ended with a version of Internet Explorer 5 in 2001 and support for it was completely discontinued in 2002. Development history In May 1996, it was reported that Steven Guggenheimer confirmed that they were looking into porting Internet Explorer to run on UNIX-like platforms, but were looking into how exactly it should be done. It was further reported that Steve Ballmer, then executive vice president of Microsoft, had shown an interest earlier in the month for a Microsoft browser to run on Unix as part of the strategy to wage the browser wars: In pursuit of a larger share of the mammoth browser market, Microsoft has been dealing with PC and workstation makers to have its IE browser bundled with newly shipping hardware. Ballmer hinted, however, that not having a Unix browser was posing an obstacle to this OEM-based strategy to try and catch up with No. 1 browser maker Netscape Communications Corp., which holds some 85 percent of the worldwide browser market with its Navigator product line. "We might just have to get one of those", Ballmer said of a Unix-based browser. In June, Microsoft entered into a contract with Bristol Technology to develop a version of Bristol's porting application Wind/U (archived) to port IE for Windows to Unix. At this time Bristol also had a contract with Microsoft allowing it access to Windows source code from September 1994 to September 1997. The project was officially announced by Microsoft at the end of July 1996 that a native version of IE for "Solaris and other popular variants of UNIX" would be finished by the end of the year, which would have "equivalent functionality as that provided in Microsoft Internet Explorer 3.0", thus "delivering on its commitment to provide full-featured Web browser support on all major operating system platforms" as well as "supporting and promoting open standards, including HTML, ActiveX and Java". However, following a dispute in March 1997 concerning each other's performance and because of contract negotiations with Bristol to access Windows source code after September 1997 failing, Microsoft reversed course and decided to directly port the Windows version in-house using the MainWin XDE (eXtended Development Environment) application from Mainsoft, the main