As Sun cranks up the hype machine for Solaris 10, one of the technologies we keep hearing about is Janus. Sun's Janus is a technology that's supposed to allow Solaris users to run Linux binaries on Solaris, unmodified.
Right now, Janus may be pushed off to a Solaris 10 update, but the irony here is striking. As noted by Con Zymaris in the eWeek article:
It used to be that Linux had to be chameleonlike and make itself appear like other platforms, such as Solaris, to advance up the enterprise. Now, Linux is the main Unix game in town, and Solaris has to be like Linux to survive.
Indeed, much was made of Linux's ability to run other platforms' binaries, including Solaris, SCO UNIX and Xenix, and other UNIX binaries. Now, Sun is playing catch-up, trying to win back market share by emulating Linux. This, of course, also points up the inherent disadvantage to closed source applications. Open source applications, like Apache or Sendmail, can simply be ported to run on a target environment.
For Linux users, the only emulation that really matters these days is the ability to run Windows applications on Linux. Thanks to Wine, CodeWeavers and (for the gamers) Transgaming, it's possible to run a wide variety of Windows apps unchanged on Linux.
One wonders how long it will be before Microsoft provides the ability to run Linux binaries on Microsoft Windows...