Virtualization technology is used to make the hardware resources expandable without having to shift the software and data from one place to another.
Virtualization is also used to lower the costs of computer hardware as multiple virtual servers can be hosted on a single server hardware.
Virtualization can be used to setup separate environments for each software application so that one application cannot interfere with the other. This is especially useful when testing a software product on different environments. Rather than dedicating a separate hardware machine, one can easily setup virtual servers on one hardware machine.
Virtualization can be used as a standardization tool. This means that we can setup one Operating System environment as a standard and then replicate the same virtual machine as many times as we want.
What is Virtualization?
According to Wikipedia:
"Virtualization (Computing) is the creation of a virtual (rather than actual) version of something, such as a hardware platform, operating system, storage device, or network resources."
Let’s take a simpler example of Virtualization. If you are a frequent computer user, you should already be knowledgeable about the partitions of your hard drive. You can create more than one partition in your computer. In Windows, the partitions are named as C:\, D:\, E:\ etc. We call all the partitions as separate drives. We also know that our computer consists of only a single physical hard drive. These drives are logical partitions of the single physical hard drive. This can be termed as Virtualization as we are creating a multiple virtual versions of a single hardware.
Types of Virtualization
Virtualization is a term which can be used with wide variety of topics but the most popular subject in which Virtualization is used is Operating System Virtualization. Operating System Virtualization means that multiple Operating Systems are being run simultaneously on the same hardware. Other types of Virtualizations include Software Virtualization, Network Virtualization, Storage Virtualization and Server Virtualization.
We’ll discuss other types of Virtualization solutions some time later but in this post we will give the most popular Operating System Virtualization solutions available for Windows.
Operating System Virtualization terminology
Before we go to discuss the actual solution, let’s first get familiar with the terminology used in Operating system Virtualization.
Host: The Operating System on which the Virtualization software solution runs is called the host.
Guest: The Operating System which is run inside the Virtualization software is called the guest.
1. VirtualBox 3.0
Oracle’s open source answer to virtualization, VirtualBox is free for both enterprise and personal use. It excels at running Linux on Windows, and also allows computers without hardware virtualization to easily run virtual machines. It runs on most platforms including Windows XP and newer, Mac OS X, and most current editions of Linux. It supports all virtual machines using the Open Virtualization Format; this includes support for virtual hard drives from Windows Virtual PC and VMware.
It also supports resizing the guest Operating System screen according to the VirtualBox window. You just need to have “scale mode” enabled for this purpose. It supports 64-bit guests (on computers with a 64 bit CPU) and the supported Guest Operating systems are – Windows NT 4.0 and newer, Solaris, most current editions of Linux
VirtualBox also comes with an extension pack which can be installed along with VirtualBox in order to get additional functionality like USB device support, remote desktop connection and PXE (network) booting capability for Intel NIC (LAN) cards.
Finally, VirtualBox allows you to run a guest OS seamlessly with your host OS using Seamless Mode. This puts the guest’s taskbar in your host OS’ desktop, allowing for full interaction with the guest operating system right inside your standard host desktop.
Pros: Simple to install and use, lots of features.
Cons: No screenshots of your guests, importing existing machines is difficult, non-intuitive disk management.
2. Windows Virtual PC
Windows Virtual PC, that is designed to run previous versions of Windows seamlessly inside Windows 7, has made desktop virtualization even more ubiquitous. Programs installed in the virtual operating system will show up in the host computer’s Start menu, and you can even set them as the default program for handling a particular file type.
Virtual PC is available as Virtual PC 2004, Virtual PC 2007, and Windows Virtual PC. It’s free, limited, true, and for people working in a strictly Windows environment, it gets the job done. Windows Virtual PC requires hardware virtualization and won’t run on computers that don’t support this. It also supports all USB devices connected to the host system, even if they are not recognized by the host system.
Windows Virtual PC can run on all editions of Windows 7, but users of the Home edition will have to create their own virtual machines from an original Windows installation disk or from old Windows installation. The supported guest operating systems are Windows XP and newer. The other operating systems (like Linux) may work but not officially supported.
3. Microsoft Virtual PC 2007
The older version of Windows Virtual PC, Microsoft Virtual PC 2007, is a free Virtualization product from Microsoft, which allows XP and Vista users to easily run virtual machines on their computers. It does everything which a standard Virtualization software can do. It can run on any computer running Windows XP or newer and does not require a processor that supports hardware virtualization. This makes it useful for Windows 7 user who wants to use the XP mode but does not have a processor with hardware virtualization.
The supported guest operating systems are – Windows 98 and newer and IBM OS/2. Other operating systems (like Linux) may work but not officially supported.
Pros: quite fast especially if you want to install any version of Windows as a guest Operating System.
Cons: No USB device support, cannot save multiple snapshots of the Virtual machine.
4. VMWare Server
VMware has been a strong player in the virtualization space for many years now and VMWare Server is a free Virtualization software from VMWare. Although its support has ended it can still be downloaded and used for free. VMWare Server supports almost all the Operating Systems as guests or hosts but 64-bit guest OS cannot be installed on a 32-bit host. VMWare Server has support for USB devices and also supports bridged, NAT and host-only network interfaces.
VMware Server is a cross-platform solution designed as a technology demonstrator for the much more expensive ESX. It has two versions – 1.x.x, which runs with local console and 2.x.x, which runs with a Web console. VMWare Server comes with administrative tools package which makes it easier to communicate between the host and the guest Operating System.
Pros: Powerful network stack; ability to connect to remote hosts, powerful command line.
Cons: Not easy to setup, especially on Linux, no 3D support, no folder sharing, limited snapshot capability.
5. VMware Player 3.0
First released in 2005 as a free solution to run pre-built virtual machines, VMware Player 3.0 is now a complete basic desktop virtualization solution that allows you to create, manage, and run virtual machines.
VMware Player runs on Windows XP and newer, and most current editions of Linux. It supports 64-bit guests (on computers with a 64 bit CPU) and offers fully integrated support for Windows and Linux guests. The supported guest operating systems are – Windows 95 and newer, DOS, Solaris, FreeBSD, and most current editions of Linux.
VMware Player supports virtual machines from all VMware products, Windows Virtual PC and Virtual Server, and Symantec backup and recovery images. It also offers a Unity mode that lets you run programs from a virtual machine alongside programs running on your main operating system – You can launch programs in the virtual machine via a program menu that appears above your standard Windows start menu.
None of the options are particularly simple to use, but the installation is quick, integration between operating systems is seamless, and the guest software runs at near native speeds. Best of all, they remain the most stable and reliable options out there. VMware Player supports all USB, Parallel, and Serial port devices connected to the host system.
Pros: Simple to install and use.
Cons: Limited functionality; no snapshots or folder sharing.
6. VMLite Workstation
VMLite Workstation is a Virtualization product based on VirtualBox (Open Source). It works very similar to Microsoft Virtual PC but gets rid of the limitations of Virtual PC. An interesting feature of VMLite Workstation is that it supports running of a 64-bit guest Operating System on a 32-bit host Operating System. So if you are running 32-bit Windows 7, you will be able to run 64-bit Windows XP with the help of VMLite Workstation.
As opposed to Virtual PC, VMLite supports saving of multiple live snapshots of the virtual machine. VMLite supports most of the Virtualization formats used in the industry like VMDK (VMWare), VHD (Microsoft), VDI (Sun) and HDD (Parallel).
VMLite comes with its own version of Windows XP Mode for Windows 7. It gives the same functionality as the original Windows XP mode and does not require any hardware Virtualization.
(Registration required to download the setup file).
7. Microsoft Hyper-V
After Microsoft VirtualPC and Microsoft VirtualServer, now there’s Microsoft Hyper-V. It works best with Windows operating systems and it powers Microsoft’s own Azure Cloud.
In the server versions of Windows, Hyper-V is installed as a server role. In the desktop versions of Windows 8 and above it is now possible to enable what is known as “Client Hyper-V” straight out of the box. Client Hyper-V allows you to enable and install Hyper-V directly through desktop versions of Windows 8, 8.1 and 10 – No need for a server OS. Hyper-V is not available in Home editions of Windows however, you’ll need Pro or Enterprise edition.
While these options are all great, we personally think the best free virtualization software listed here is VirtualBox, it’s available to use on more platforms than others and is open source.
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