CIS 170F: Windows 7 Administration

Week 4

Managing Disks
Virtual Disk Management Tasks
The Virtual Machine

  • If you need access to multiple OSs primarily for testing purposes rather than for long periods of work, there's another way to use multiple OSs without the hassle inherent to multiboot setups. In fact, you can even use multiple OSs simultaneously on the same computer. It's done with a setup called a virtual machine.
  • A virtual machine program emulates (simulates) in software all the hardware functions of a PC. It lets an entire operating system (called a guest operating system) run as an ordinary application program on a host operating system such as Windows 7. Because all the hardware functions are emulated, the guest OS doesn't "know" it's not in complete control of a real physical computer. When the guest OS requests access to a hard disk, display card, network adapter, or serial port, the virtual machine program calls upon the host OS to actually carry out the necessary operations.
  • Another advantage of the virtual machine programs currently on the market is that they don't allow a guest OS unfettered access to your real disk drives. Instead, you create a virtual disk, a single large file on your host OS that contains what a virtual machine sees as a hard drive.
  • A virtual machine can let you run as many OSs and as many configurations of these OSs as you like, separately or simultaneously. And all this comes without the hassle of editing the Windows 7 boot menu or worrying about partitions.
  • The Windows version of Virtual PC 2007 is a free download that anyone can use. In general, the experience for non-Windows OSs on Virtual PC is not as good as with VMware Workstation. However, it's free, so we can't complain too much. Be sure to download the Virtual PC extensions and give a Windows 7 Virtual PC at least 1GB of memory (a setting in Virtual PC) for it to run with any appreciable speed. This requires that at least 1.5GB of physical RAM in your host PC.

    • Versions of the Microsoft Virtual PC are available for Windows and for the Mac at http://www.microsoft.com/virtualpc.

  • With each copy of Windows 7 Professional, Ultimate, and Enterprise comes the ability to use a Microsoft download called XP Mode, aka XPM. Basically, this includes Virtual PC plus a virtual machine image (VHD) and settings (VMC) files with Windows XP SP3 preinstalled. Microsoft also grants a "free" license to use this guest OS, thereby saving users the expense of acquiring one of their own. One word of warning, though: The XPM version of Virtual PC requires host processors to support hardware virtualization, which means that older PCs can't run it.