QuickTransit actually incorporates two key functions - CPU instruction translation and OS call mapping. In the case of QuickTransit for Solaris/SPARC-to-Linux/x86-64, for example, each time the application invokes a Solaris OS call, the corresponding Linux call is made. Since there is not a one-to-one correspondence between the two operating systems, QuickTransit has to "fill the gaps" to make sure each OS call is implemented correctly. In some cases, Transitive has written the appropriate code to resolve the call, but in most cases we use an implementation of OpenSolaris to provide the functionality required. Transitive also provides a Solaris package search facility on its Web site to help customers with applications that rely on more esoteric libraries.

As for the title question, there are of course a few applications that cannot be run via QuickTransit, and these are generally those where "rules have been broken" during development. For example, an application that has modified the Solaris kernel in some way is unlikely to run using QuickTransit. Likewise, applications that are dependent upon proprietary hardware in the original system are also likely to have problems. As with VMware itself, there is a small number of applications that cannot be virtualized in this way. But for the vast majority of commercial, open source and in-house Solaris/SPARC applications that have been developed using standard tool sets and adhered to Sun's application binary compatibility (ABC) standards, replication on x86 platforms using cross-platform virtualization works just fine.