CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [42]
Transitioning to 64-bit Windows
Techs use the x# terminology to describe a particular computer architecture, implying that there is some compatibility within that architecture. This matters because people need some comfort that the software they purchase will work properly with the computer they have. The transition from 32-bit versions of Windows to 64-bit versions of Windows requires a certain update in terminology.
x86 versus x64 Intel originally used numbers to name its CPUs, such as 8086, 80286, 80386, and so on. To talk about them collectively, the industry replaced the leading numbers with an x and kept the numbers that stayed consistent for all the processors, thus x86 describes the Intel CPU architecture for PCs. All the 32-bit versions of Windows were designed to run on x86 architecture.
The move to 64-bit CPUs and, equally importantly, to 64-bit versions of Windows required some sort of change in terminology. Microsoft and others picked up the x# terminology and changed it to market 64-bit-only versions of their software, branding the 64-bit software as x64. A consumer, therefore, could look at a product such as Windows XP Professional x64 Edition and very quickly know that the software was designed for 64-bit CPUs rather than 32-bit CPUs.
The two x# uses—x86 and x64—don’t really compare, but that’s okay. Computer people love the letter X almost as much as car manufacturers do.
Software Compatibility Transitions to updated architecture, such as the change from x86 to x64, creates concern among users, because they fear that their old programs won’t run or will run poorly, or that they’ll have problems with compatibility down the road. Techs need to allay those fears by educating users properly. Here’s the scoop in a nutshell.
Most of the 64-bit processors run either 32-bit or 64-bit versions of Windows without missing a beat. The 64-bit versions of Windows require a 64-bit CPU; they snicker at 32-bit (or x86) processors and refuse to play. Many companies have produced 64-bit versions of application software that only works with 64-bit Windows running with a 64-bit CPU. Great, right? But what about all those 32-bit applications out there working for a living? It gets interesting.
Windows Vista 64-bit versions support most 32-bit applications, sometimes without any user intervention and sometimes through explicit use of the Windows compatibility mode options. (Just for the record, you sometimes need to use Windows compatibility mode options to run older programs on Windows Vista 32-bit versions, so it’s not just a function of 64-bit support for 32-bit apps.) Windows can try to emulate previous versions of Windows if an application balks at loading.
To run a program in an emulated version of Windows, you need to access the primary executable file that, when double-clicked, makes the program run. We’ll go through where to find your program files in the various versions of Windows later in this chapter, but a quick example should suffice here. A user has a custom program—called “Widgets for XP”—designed to take advantage of particular features in Windows XP Professional with Service Pack 2 installed and it doesn’t work in Windows Vista. Open Computer and go to C:\Program Files\Widgets for XP and look for a file with the type listed as Application, such as WidgetsXP.exe (Figure 4-14). Right-click and select Properties.
On the Compatibility tab, you can select the checkbox next to Run this program in compatibility mode for: and select the OS of choice (Figure 4-15). In this case, we would select Windows XP (Service Pack 2) to provide optimal compatibility for the application. Windows saves the configuration change and tries to open the program in compatibility mode each time the program loads.
Figure 4-14 Finding an executable file
Figure 4-15 Compatibility mode options
The Windows Interface
All versions of Windows share certain characteristics,