When I have asked in the past VMWara has stated that what is the point of a 64-bit rewrite if all it is buying you is more memory when the current 32-bit version already extend the memory beyond normal 32-bit limits.
Well not to get into specific details, but I work for a software company. We have MANY 20+ year developers on Assembler, C++ and various others. There is MUCH more to 64-bit programming than simply increasing memory constraint. There are performance considerations. LARGER address spaces, etc..
The list for why we SHOULD have 64-bit is endless.. and every programmer (that knows the true benefit) will tell you that 64-bit is where we should be, no question.
However, programmers (true programmers) is tough to make good 64-bit apps, it's infinately more complex. It's not a simple recompile. In order to reap the benefits of 64-bit it pretty much requires a true rewrite, and you have really really understand Intel Architecture.
So 64-bit is not just an extension of memory, there are so many variables, it would require an entire encyclopedia to explain.. but suffice to say, that ESX would run much better than the current level.. which is why it's coming later... Itanium is another discussion, but 64-bit would offer much more threads, processes, driver enhancement, memory limitations (conceivably there really isn't any).. 32-bit is very constraining.. but it's easier. 64-bit offers more, but it's much more to program and requires a thorough knowledge of the architecture.
VM Ware even acknowledges their limit of 32-bit programming, but it takes a lot of planning and changes to their code..which is why we haven't seen it.... YET. Stay tuned for announcements... Maybe VM World 2008 -- which is WHY I am very excited about going...
