BaaN claims that they support different types of operating systems (Windows, Unix, Solaris, HP-UX, AIX) to connect to. Using middleware and BOIs. Is this really true and as flexible as they claim? Are there restrictions, or Operating Systems on wich this doesn't work properly?

David

Aye 't is true.
Baan uses virtual machines to connect to OS and databases, allowing the source code to stay more or less generic.
Off course you require different porting sets to communicate with different systems, so there is always room for unexpected surprises but in general Baan can (be tuned to) perform well on any system.

Of course this flexibility comes at a price too.