Despite the relentless march of Linux, major vendors believe commercial Unix releases aren’t ready for the scrapheap yet. As Linux evolves from its single-processor roots into larger-scale applications, many market watchers have predicted that it will eventually replace the remaining commercial Unixes: Hewlett-Packard’s HP-UX, Sun Microsystem’s Solaris, IBM’s AIX and SGI’s Irix. “It costs between $150 million and $200 million a year to generate your own Unix system and you then have to say to yourself ‘Am I going to see that amount of extra revenue if I put in these features?'” Linux International executive office Jon ‘maddog’ Hall told iTnews. However, Unix vendors argue that the needs of large-scale enterprise users haven’t yet been met by Linux.