In theory, QuickTransit can support any operating system that is Unix-like or Linux-like as a source application platform and move it to any other Unix-like or Linux-like platform. The software can also move any applications (including the operating systems) that run on IBM mainframes to a Unix or Linux platform. This was in there by design.
When I asked Transitive if it could support RPG applications and their associated DB2/400 databases on a Unix or Linux platform, I was told this was absolutely possible. It is reasonable to assume that other proprietary environments - HP's MPE and OpenVMS platforms come to mind - could be emulated in a similar fashion.
Transitive has seen steady adoption of its QuickTransit tool. Most famously, QuickTransit was used in 2005 by Apple to emulate applications written for PowerPC-based Macs to run on its X64 machines. Silicon Graphics went public first, just before Apple, using QuickTransit to support applications written for Irix workstations on its Altix Itanium-Linux servers. Hewlett-Packard licensed QuickTransit to be able to run Sparc/Solaris applications in emulation mode on its ProLiant X64 servers running Linux, and Sun Microsystems did a defensive maneuver, choosing QuickTransit to port Sparc/Solaris applications to its own X64/Solaris servers.
Significantly, IBM itself licensed QuickTransit, weaving it into a product called PowerVM Lx86, which came out in April of this year, allowing 32-bit X86-Linux binaries to run unchanged on Power-based AIX or Linux servers. (This tool was available as a beta under the name System p Application Virtual Environment, or PAVE, and started shipping with AIX 6.1 in November 2007.) To date, more than 16 million instances of QuickTransit are running - most of them on Apple Macs.
The Mac connection might be important. Remember that IBM's top Power nerd is trying to jump ship and move to Apple? Well, IBM and Mark Papermaster have been arguing back and forth in the courts, and Steve Jobs, Apple's top dog, doesn't have the nerd he wants to help him create chips for the iPhone and iPod because IBM is worried that Papermaster's skills will help Apple in the PC and server business. And now, IBM is getting in position to buy the secret sauce behind the Mac running Power apps on Intel-based machines. Imagine if Apple was planning to create its own Power-compatible chips, having bought PA Semi, and then not needing emulation at all. This may all be a coincidence, and if it is, it is surely funny just the same.
But seriously, IBM now controls the software that HP was using to attack the Sparc server base and that Sun was using to try to preserve it on X64 iron without requiring customers to do a port. Sun has just introduced legacy Solaris containers (virtual private servers, as distinct from virtual or logical machine partitions) that allow Solaris 8 or Solaris 9 instances (including their apps and settings) to run on Sparc machines. However, Sun's licensed version of QuickTransit was the only way short of recompilation to get some Sparc apps written on earlier Solaris releases to move over to new Opteron or Xeon iron.