While Microsoft execs and those who’ve managed to get their hands on early builds of Windows 7 have focused largely on user-interface tweaks in Windows 7, there will be some under-the-covers changes, too. Microsoft officials have said on the record that deep-level changes between Windows Vista and Windows 7 will be kept to a minimum, in order to insure application and driver compatibility. Yet Microsoft officials acknowledge that Win32, the core of Windows, is not suited for asynchronous, concurrent computing.