Windows® Virtual PC (WVPC) is a client virtualization software, which can be used on Windows 7 to create multiple Virtual Machines (VMs), each running a different operating system (OS). WVPC can be obtained as a free download from Windows Virtual PC website. WVPC is the engine which supports Windows XP Mode, a preconfigured VM running Windows XP SP3 provided by Microsoft on Windows Professional, Ultimate and Enterprise SKUs.

A VM functions as an additional PC on your Windows 7 desktop, complete with its own Start menu, applications, folders such as My Documents, access to the network for email and Internet, and access to USB and serial devices. Installing WVPC creates a short-cut named “Windows Virtual PC” on Windows 7 Start menu (Figure 1). Clicking on the shortcut opens the Virtual Machines folder, with a command bar that has an option to create a new VM. You can create a new VM using a guest OS image (e.g. Windows XP SP3 DVD or ISO image, or a VHD containing the OS image).

Figure 1. Start menu integration of Windows Virtual PC, VMs and virtual applications

WVPC supports Windows XP SP3, Windows Vista SP2 and Windows 7 as the guest OS. To the guest OS running in the VM, WVPC presents a virtual hardware, complete with disk, CPU, memory, I/O and other devices. Virtual Machine Monitor (VMM), a kernel-level component running on the host OS, manages the instructions from the VM for all the guest VM operations such as CPU, disk and I/O access, device and network access.

Key Features in Windows Virtual PC

• WVPC is seamlessly integrated into the Windows desktop. This enables you to launch and use a full VM or a virtual application as if it is just another native Windows 7 application, and navigate between the host and guest environments and applications freely. This is provided via features such as clipboard sharing, printer sharing, Start menu integration, file system and drive sharing, and file association with host.
• WVPC comes with a new UI including a full VM Console, Settings interface and a WVPC Wizards interface to create new VMs, and advanced management of VMs using diff disks. 
• Windows XP Mode, a preconfigured Windows XP SP3 VM, is provided with WVPC on Business SKUs, to easily create and setup a virtual XP desktop which gets integrated with the Start menu.
• WVPC can run in two modes: a Virtual Applications mode to run legacy applications seamlessly, and a full desktop mode that gives the user a full desktop experience of the guest operating system. 
• Printers, flash memory sticks, external hard disks and backup disks, digital cameras and smartcards are USB devices important to the Enterprise and SMB users, which can be used easily in WVPC VMs.
• WVPC provides extensive networking capabilities to a virtual machine. You can configure network connections between a VM and the host, among multiple VMs, and between VMs and the external network. 
• COM scripting support and headless VM support are provided, with an SDK for developers and IT Pros to extend the basic WVPC functionality to enable their unique scenarios.
• WVPC takes advantage of Hardware Assisted Virtualization (HAV) feature (Intel® VT and AMD-V™) which improves the performance and robustness of VMs on HAV-capable hardware. HAV is required to use WVPC on Windows 7.

In the upcoming blog articles, we will dive into how each feature and component of WVPC was engineered and how to use them in different scenarios. In this first article, we will focus on seamless application compatibility, which is the key scenario WVPC enables.

Seamless Application Compatibility

Windows 7 is built to effectively address the application compatibility need, using the Application Compatibility features provided in-box. Windows XP Mode is an additional solution specifically targeting Windows XP application compatibility. It is a preconfigured VM, created using a pre-activated and sys-prepped copy of Windows XP SP3 in VHD file format. It will be made available on the Download Center as a separate EXE package containing a VHD (with XP SP3) for installing on Windows 7.

Using a VM as a Full Desktop on Windows 7

In Figure 1, clicking on the shortcut to Windows XP Mode launches a full XP desktop in a VM (Fig. 2). User is able to run Internet Explorer® 6 and Excel® 2003, two LOB (Line of Business) applications, in XP Mode in this way. Notice the XP Taskbar within the VM right above the Windows 7 super bar, on which Excel and IE6 icons are shown. The full VM also provides a toolbar (at window top) with different options to interact with the VM. For example, expanding the ‘Action’ dropdown menu item presents options to view the same VM in full screen mode, to restart, sleep or close the VM. The Tools menu item presents a shortcut to VM Settings. Clicking on it launches the Settings dialog where user can specify any changes in VM memory, networking options, logon credentials and other settings. The Ctr+Alt+Del option is necessary to shutdown the VM, whereas clicking on the (X) icon on the far right would close the VM as per the user’s preference specified in Settings (i.e., hibernate, logoff or shutdown). These features and scenarios will be discussed in detail, in future blog articles.

Figure 2. A VM created using an XP guest OS running on a Windows 7 desktop

Virtual Applications: Running your Windows XP Applications seamlessly on Windows 7

In the above full VM scenario, to run an LOB app (Excel 2003), user has to launch the XP VM first and then start the application within the VM. WVPC offers a much more seamless solution to application compatibility, via the Virtual Applications and Windows XP Mode features. Virtual applications are seamlessly integrated with the Windows 7 desktop and Start menu. When an application is installed in the XP Mode VM, a shortcut gets automatically created on the Start menu of Windows 7 (Figure 3). Notice the shortcut link to Internet Explorer 6 and Excel 2003 – two virtual applications. Clicking on the Excel shortcut will launch that application. Virtual applications icons can also be integrated with Windows 7 notification area (Systray). Files created using such applications have their file association enabled, which means that, clicking the file’s icon shortcut will also launch the required virtual application and open the file. Book1.xls, an Excel 2003 file, has its shortcut placed on Windows 7 desktop. Such virtual application files can be saved in the host My Documents folder or the Desktop.

Launching the first virtual application starts the underlying VM, automatically logging the user in. Launching of subsequent applications is much faster. Notice the shortcuts to Excel and IE6 pinned to the Windows 7 super bar, and appear in a jump list as well. Such seamless integration with Windows 7 Shell is designed to facilitate a simple, delightful experience using legacy apps.

Figure 3. A virtual application, Excel 2003, running in seamless mode on a Windows 7 desktop

In Closing…

The central vision of WVPC is to drive the overall adoption of Windows 7 by addressing the legacy application compatibility needs of enterprise and small business users with a very simple, readily accessible and seamless presentation of applications and virtual desktops. We will blog about these features and scenarios in detail soon. Watch this space, and welcome to the Windows Virtual PC and Windows XP Mode experience on Windows 7!

Prasad Saripalli

Principal Program Manager

Microsoft Virtualization Team