Althea wants to know what the difference is between Virtual PC and Virtual Server, and when she would use one versus the other. The fundamental difference between Virtual PC and Virtual Server is that Virtual PC is designed for desktop (or "client" or "PC") operating systems and Virtual Server is designed for server operating systems. As a result, the usage scenarios for the two products are correspondingly different. There are a few feature differences as well. This article covers the major functional differences between the two products.

Supported operating systems

For Virtual PC, both the host operating system (the one you install Virtual PC itself on) and the guest operating systems (the ones running inside virtual machines) will be desktop operating systems. Supported host operating systems include Windows XP Professional, Windows 2000 Professional, or Windows XP Tablet PC Edition. Supported guest operating systems include these plus a number of others, such as Windows 98 and MS-DOS 6.22. See the Virtual PC documentation for a complete list.

For Virtual Server, the host operating system and the guest operating systems will be server operating systems. Supported host operating systems are Windows Server 2003 (Standard, Enterprise, and Datacenter Editions) and Windows Small Business Server (Standard and Premium Editions). Supported guest operating systems include these plus Windows 2000 Server, all editions except Enterprise as well as Windows NT Server 4.0 Enterprise Edition SP6a. See the Virtual Server documentation for more information.

Usage scenarios for Virtual PC

Some primary usage scenarios for Virtual PC are:

• Support for legacy desktop applications. For example if you have applications  that were designed to run on Windows 98, but won’t run on your new Windows XP machine, you can run Windows 98 and your application in a virtual machine. Ben Armstrong uses Virtual PC to run his favorite DOS-based computer games. (For more info, see Ben's blog at http://blogs.msdn.com/Virtual_PC_Guy.)
• Help desk. If you're a  help desk technician, you could set up a variety of desktop environments inside virtual machines to duplicate those of you client’s, so you could reproduce problems when clients call in.
• Desktop application testing. If you're a developer, you can use virtual machines to test desktop applications in a variety of operating system environnments.
• Training. If you're a trainer, you can set up your training programs to run inside virtual machines. This way you can offer more types of classes. In addition, you can set up the virtual machines to discard changes that were made during the class. This reduces setup time dramatically.

These scenarios are described in detail in the white paper at: http://www.microsoft.com/windows/virtualpc/evaluation/techoverview.mspx.

The uses that you can find for Virtual PC are limited only by your resourcefulness, though. For example, my co-worker Nehar has Virtual PC set up for his wife and kids to use for browsing the Internet. That way he doesn’t have to worry about anything they download because it won’t affect the host operating system. If the virtual machine get’s corrupted or infected, he can simply delete it and start over.

Usage scenarios for Virtual Server

Some primary usage scenarios for Virtual Server are:

• Test and development for server applications. You can use Virtual Server in situations that require rapid and frequent server reconfiguration, as required with development and testing, product demonstrations, and training.
• Application migration. You can move server applications running on older hardware and operating systems, such as Microsoft Windows NT® Server 4.0, onto virtual machines on newer, more resilient systems running Microsoft Windows Server 2003 operating systems, without rewriting the applications.
• Server consolidation. Many companies have departmental and branch office servers that are underutilized. You can consolidate applications that require different server operating systems onto a single physical server to reduce the number of physical servers you need to maintain.

Other differences between Virtual PC and Virtual Server

Virtual Server provides a few features that aren’t available in Virtual PC:

• Remote Management. You can administer Virtual Server remotely by using the Administration Web site.
• Scalability.  Virtual Server scales across multiple processors (although in the current release each virtual machine can take advantage of only one CPU).
• COM API.  You can manage Virtual Server and its virtual machines by using the COM API. For more information, see the Virtual Server SDK that ships with the product.
• SCSI support. Virtual Server provides SCSI support.
• Multiple CD-ROM drives: Although Virtual Server allows for virtual machines with multiple CD-ROM drives, Virtual PC supports virtual machines with only one CD-ROM drive.

On the Virtual PC side, Virtual Server does not include an emulated sound card in its virtual machines, while Virtual PC does.

That about sums it up as far as important functional differences. I hope this answered your question, Althea.

If your virtual machines consistently hang or your keyboard and mouse behaves irratically, you can try one or more of the following remedies:

1. First of all, if the virtual machines are hanging, make sure you've got enough available memory and CPU for the combined requirements of the currently running virtual machines as well as the host. If there aren't enough system resources available, then turn off one or more virtual machines.
2. If the virtual machines are running on a Dell notebook computer with SpeedStep power management, go to the Dell Web site and install the latest version of the SpeedStep utility (http://support.dell.com/). If this doesn't work, try removing SpeedStep by using Add or Remove Programs or disabling SpeedStep in your BIOS. If you don't want to remove or disable SpeedStep, you can use the "Always on" Power management profile on the notebook computer.
3. If you haven't updated your Virtual Machine Additions, but you've upgraded Virtual Server from a pre-release version, or if you created the virtual machine in Virtual PC, install the release version of Virtual Machine Additions. For instructions, see the Virtual Server 2005 Administrator's Guide.
4. If you are running an anti-virus program, add *.vhd, *.vsv and *.vud files to your exception list. Be aware that the list may be reset when you upgrade your anti-virus program.
5. Log on as a different user to see if the problem goes away. If it does, your Windows user profile may be corrupted, which can cause the system to lock up when you right-click an item in Windows Explorer. See this KB article information about this issue: http://support.microsoft.com/default.aspx?scid=kb;en-us;555021&Product=winxp 
6. If you're using Virtual PC 2004 with a European keyboard, the keyboard may lock up when you type Alt+G+R to create a backslash. To fix this problem, install Virtual PC 2004 SP1, which you can download for free from: http://www.microsoft.com/downloads/details.aspx?familyid=b07c9ef0-265a-4237-ae3b-25bc8937d40f&displaylang=en.
7. On Virtual PC 2004, you will probably experience performance issues with virtual machines running Windows XP with Service Pack 2. This is because XP SP2 was finished after Virtual PC 2004 was released. To fix the problem, install Virtual PC 2004 Service Pack 1. You can download it from http://www.microsoft.com/downloads/details.aspx?familyid=b07c9ef0-265a-4237-ae3b-25bc8937d40f&displaylang=en.
8. Verify that your hardware acceleration setting is set to full (right-click your desktop, click Properties, click the Settings tab, click Advanced, click the Troubleshoot tab.)

When you add a network adapter to the host computer (including a Loopback adapter) the new adapter won't appear as an option on the Network Properties page for any virtual network, so you won't be able to connect a virtual network to it. To fix this problem, you need to enable the Virtual Machine Network Services driver on the adapter, as follows:

1. On the host computer, click "Start," click "Control Panel," and then click "Network Connections."
2. Right-click the connection that uses the new network adapter and click "Properties."
3. On the "General" tab, select the "Virtual Machine Network Services" check box, and then click "OK."

The network adapter should now appear in the "Network adapter on physical computer" list on the Network Properties page of any virtual network.

You can follow this procedure any time Virtual Server doesn’t recognize a network adapter. This is a rare occurance, but if there's already a virtual network configured on this network adapter, you'll have to remove from the virtual network any virtual machines that are using it and then re-connect them. Otherwise the virtual machines won’t have network connectivity. You do this as follows:

1. Open the Virtual Server Administration Website.
2. In the left pane under "Virtual Machines," point to "Configure" and click the virtual machine.
3. In the lower part of the page, click "Network adapters."
4. Click "Remove" and then click "OK."
5. In the lower part of the page, click "Network adapters," and click "Add Network Adapter."
6. In the "Connected to" box, select the network adapter to use, and then click "OK."

Hi, I'm Megan Davis, a technical writer at Microsoft. I helped write the documentation for Virtual Server 2005 and wrote all of the documentation for Virtual Server 2005 Migration Toolkit and Virtual Server Management Pack for MOM 2005. I started this blog while working on Virtual Server, and although I recently moved to the BizTalk Server team, still have lots left to say about virtualization, so will keep blogging on it.

On this blog I've provided some links that I hope you'll find helpful. In addition, I monitor the newsgroups for popular topics to write about. If you have requests for particular information or know of other links I could include, I hope you'll send them to me.

Thanks for stopping by. Have a great day!
Megan

PS - By popular demand, here's a photo of the Windows Server Core Content team. I'm in the front wearing sunglasses. From left to right: Trina, Althea (the boss), me, Joe, Cynthia, Jan, Kathy, Michael, and Jill. Patrick is taking the picture.

http://megandavis.members.winisp.net/resources/WindowsServerCoreContentTeam.jpg

(Updated to correct an error: You want to enable DCOM for Authenticated Users rather than Everyone.)

On Windows XP SP2, you may no longer be able to open the Administration Website, although you could before you installed Windows XP SP2. This is due to tighter security measures in Windows XP SP2. To fix the problem, either uninstall and reinstall Virtual Server, or else do the following:

1. Click "Start," click "Control Panel," and then double-click "Administrative Tools."
2. Double-click "Component Services."
3. Expand "Component Services", 'Computers," "My Computer,' and "DCOM Config."
4. Right-click the first instance of Virtual Server in the list, and then click "Properties."
5. On the "Security" tab, in "Launch Permissions" click "Edit."
6. Select "Authenticated Users" and then, next to "Launch Permission," select "Allow." If "Authenticated Users" doesn't appear in the list, you'll need to add it before you can take this step.

If you've installed (the currently pre-release version of) Windows Server 2003 SP1, the same issue may exist. If you can’t open the Administration Website locally, you can try configuring your LAN settings so that the proxy server is bypassed for the Administration Website URL, as follows.

1. In Internet Explorer, click "Tools" and then "Internet Options."
2. On the "Connections" tab, click "LAN Settings" and then "Advanced."
3. In "Exceptions," type the full URL of the Administration Website, and then click "OK."

You can also try changing the DCOM configuration, as for Windows XP SP2. The UI is slightly different, though:

1. Click "Start," point to "Administrative Tools," and then click "Component Services."
2. Expand "Component Services," "Computers," "My Computer," and "DCOM Config."
3. Right-click "Virtual Server" and then click "Properties."
4. On the "Security" tab, in "Launch and Activation Permissions" click "Edit."
5. Select "Authenticated Users" and then next to "Local Launch," select "Allow." If "Authenticated Users" doesn't appear in the list, you'll need to add it before you can take this step.
6. If you want to also allow remote DCOM, next to "Remote Launch," select "Allow."

This post explains the items in the Toolbox (a set of links to the left of this pane).

Virtual Server 2005 Migration Toolkit (VSMT). This is a set of command-line tools and executables that you can use to help automate the migration of physical servers to virtual machines. VSMT is a free download from Microsoft. The documentation is hard to find (I wrote it, but didn't get to say where it's installed). You can find it in Program Files\Microsoft VSMT. Here's the link to the download page: http://www.microsoft.com/windowsserversystem/virtualserver/evaluation/vsmt.mspx

Solution Accelerator for Consolidating and Migrating LOB Applications. This document from Microsoft provides detailed guidance for consolidating and migrating Windows NT® 4.0-based applications in heterogeneous or mixed workload environments. I mention it here because it covers using VSMT (above) to help consolidate multiple servers running Windows NT 4.0 onto virtual machines running in Virtual Server. One of my best friends, Linda Wells, helped write this solution accelerator, and I think it’s really great! Here's the link to the download page: http://www.microsoft.com/technet/itsolutions/techguide/msa/solacc/lobsa/default.mspx

Solution Accelerator: Patch Management Using Systems Management Server 2003. This solution accelerator provides sample automation scripts and reporting that will assist you in the four-step patch management process of Assessing, Identifying, Evaluating and Planning, and Deploying software updates with Systems Management Server 2003 (SMS). It's based on Microsoft Operations Framework (MOF) and built on SMS. Sample scripts assess Virtual Server 2005 and Virtual PC 2004 installations. They assess host and guest operating system type, Virtual Server 2005 guest state (saved, stopped, running), Undoable mode (enabled/disabled), and combination reporting, which joins host and guest sessions into a single view that allows you to prepare for end-to-end patching of systems running in virtual machines. Here's a link to the abstract: http://www.microsoft.com/technet/itsolutions/cits/mo/swdist/pmsms/2003/pmsms031.mspx

Running Domain Controllers in Virtual Server 2005. This document is intended for IT administrators, engineers, and architects who are evaluating using Virtual Server to host domain controllers that are running Windows Server 2003 or Windows 2000 Server in virtual machines.
http://www.microsoft.com/downloads/details.aspx?FamilyId=64DB845D-F7A3-4209-8ED2-E261A117FC6B&displaylang=en

Platespin Power P2V. This is a new product offered by PlateSpin to migrate physical computers to virtual machines (P2V) and virtual machines to virtual machines (V2V). I haven’t tried the product, but the Web site says it has automated functionality that “allows users to "drag-and-drop" servers quickly and easily, without manual labor.” Here's a link to the product page: http://www.platespin.com/Products/PowerP2V_Virtual_Server.aspx

Using Virtual Server 2005 to Create and Configure a Two-Node Cluster. How to build a two-node VM-VM cluster on a single host by our very own clustering guru, Robert Larson. Here’s the link:
http://www.microsoft.com/technet/prodtechnol/virtualserver/deploy/cvs2005.mspx

There is no Word version available on the web for download yet, but one has been requested. There will also be a link to this article from the main Virtual Server TechNet page and we have requested a link directly from the Virtual Server product page. These links aren’t live as of this writing.

 On December 9, 2004, 12:30 p.m. Pacific Time, Robert Larson will be showing us how to create a two-node cluster of virtual machines running Windows Server 2003—a key feature of Virtual Server 2005. To register, go to: http://www.microsoft.com/windowsserversystem/virtualserver/techinfo/events/default.mspx.