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Client-Side Virtualization Purpose and Requirements of Virtualization In a business environment, companies must manage technological resources in a way that allows them to stay competitive by cutting costs and allocating resources wisely. As a result, client-side virtualization has become a popular method of providing staff with critical resources, such as applications, file-sharing services, and other productivity tools. Virtualization also has advantages for SOHO users, because it can provide access to programs that are not available on a specific OS.

PC virtualization occurs when a host machine uses its system resources to host a virtual machine. A virtual machine is sometimes called a guest. A host machine must be a physical machine that is powered on and controlled by a user. A virtual machine uses the system resources on the host machine to boot and run an OS. The OS of the virtual machine is independent of the OS installed on the host machine.

Hosting a virtual machine allows users to access the functionality and resources provided by an OS that is completely isolated from the OS of the host computer. For example, a host machine running Windows 7 can host a virtual machine that has Windows XP installed. This virtual machine can run software specific to Windows XP. The Windows XP installation does not interfere with the Windows 7 installation on the host machine. If needed, users can further increase the functionality of their system resources by running multiple virtual machines.

Hypervisor: Virtual Machine Manager The software that creates and manages a virtual machine on a host machine is called the hypervisor, or Virtual Machine Manager (VMM). A hypervisor can run multiple virtual machines on a single host computer. Each virtual machine runs its own operating system. The number of virtual machines that can be made available depends on the host machine’s hardware resources. The hypervisor allocates the physical system resources, such as CPU, RAM, and hard drive, to each virtual machine as needed. This ensures that the operation of one virtual machine does not interfere with another.

There are two types of hypervisors: Type 1 (native) and Type 2 (hosted). A Type 1 hypervisor runs directly on the hardware of a host and manages the allocation of system resources to guest operating systems. A Type 2 hypervisor is hosted by an OS. The Windows Virtual PC is an example of a Type 2 hypervisor.

Windows Virtual PC

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Windows Virtual PC is the virtualization platform for Windows 7. Virtual PC allows you to partition system resources for a Windows OS among virtual machines running a licensed copy of Windows 7, Windows Vista, or Windows XP. You can download Virtual PC from the Microsoft Windows website. The figure displays the hardware requirements for running Virtual PC. Virtual PC is required to run the Windows XP Mode program in Windows 7.

Windows XP Mode

Windows XP Mode is a program available for Windows 7 Professional, Enterprise, and Ultimate. Windows XP Mode uses virtualization technology to allow users to run Windows XP programs in Windows 7. It opens a virtual machine on the Windows 7 desktop that provides a fully functional version of Windows XP, including access to all system resources. After installing a program in Windows XP Mode, you can run the program in XP Mode and access it from the Windows 7 Start Menu.

NOTE: Before using Windows XP Mode, download and install Windows Virtual PC.

To access XP Mode in Windows 7, follow these steps:

Step 1. Select Start > All Programs.

Step 2. Select Windows Virtual PC > Windows XP Mode.

Virtual Machine Requirements

All virtual machines require that basic system requirements are met, such as a minimum amount of hard disk space or RAM. The minimum system requirements for Windows Virtual PC are displayed in the figure.

Like physical computers, virtual machines are susceptible to threats and malicious attacks. Users should install security software, run the Windows Firewall, and update patches and drivers.

To connect to the Internet, a virtual machine uses a virtual network adapter. The virtual network adapter acts like a real adapter in a physical computer, except that it connects through the physical adapter on the host to establish a connection to the Internet.