When people speak of virtualization on the iPad, they are referring to a remote desktop session to a hypervisor. In short, an iPad remote desktops into a host computer running the virtualize operating system. You can't quite yet use an iPad as an x86 host hypervisor.
Today, I am going to review Parallels 7 Mobile Access. Parallels 7 is a popular Virtualization application for Mac OSX. The mobile client has been billed as "retina" ready so I decided to take it for a spin.
Why not VirtualBox? I'm a big fan of VirtualBox (VB). I use it on all my computers and I like the fact I can move VMs across platforms. I use VB for testing all my console OS (server builds). However, for rich GUI driven OSes, Parallels is much faster, has better Mac OS integration, and a better user experience. Most notably, it has an excellent mobile client.
In some hypervisors like VirtualBox, you can set up an RDP (Remote Desktop Protocol) port and use an RDP client on the iPad to access to virtual machine. The screenshot below shows how one can set up and configure RDP access in VirtualBox. The only problem with this method is that you must be on the same subnet as the VM host; meaning you must be in the same network. Furthermore, your experience will be totally dependent on whatever RDP client you are using. Some of the RDP apps are hit-or-miss on the App store.
Parallels Mobile Access's major key features are tunnelled access and Retina display support. Those may be two compelling reasons to choose Parallels over something like VirtualBox.
The Main menu allows you to instantly access your available VMs.
With a simple signon to Parallel's centralize servers, you can access your VM hypervisor from anywhere. Even behind firewalls, there is a secured tunnelled access (akin to reverse NAT) to your Macintosh from your iPad. Another key unique feature is the ability to start and close VMs. Compared to VirtualBox, you can remotely boot up your VM. VirtualBox can be setup using a 3rd party web based client or you can remotely start up VM from an SSH session but that is a different topic for a different day. In short, Parallels makes it easy to start and stop VM.
Parallels Mobile Access has a good set of multi-touch gestures for things like enabling the soft keyboard, right-click, double click and hiding the touch menus. Overall it works good except with a high res display, you really need to be patient and zoom-in when you deal with vertical scrollbars such as those on web browsers.
In Parallel's Modality or Window mode, you can run the VM's resolution independent of the host computer. What this means is you can pump up the resolution to as high as you want on the iPad.You can run at 1920x1200, 1680x1050 and as high as WQHD (2536x1440). With the iPad's retina screen, you can rub 2536x1440 with amazing clarity. The scaled screenshot below cannot convey the breathtaking clarity and sharpness. Running Linux Mint 13 Cinnamon, the VM display is absolutely gorgeous. Typeface, window transparencies, icons, and graphics are super sharp on the iPad 3's 9.7" HiDPi screen.
Look at the real estate available on a 2536x1440 workspace!
There are many great uses on why one would use an iPad as a hypervisor client. I recently bought some old Macromedia based DVD interactive Disney learning games for my son. I failed to read the box requirement and notice it supports Windows 95-98 and Mac OS9. Running on a live Window 7's laptop is horribly painful because most modern computers are not good at scaling to 256-colors at 800x600 resolution. On a 15" HP laptop,my son's Disney program takes up 1/4 of the screen and the rest is filled in black. Furthermore, children now are used to point-n-click touch screen tablets. He has a hard time accidentally right-clicking a mouse which often closes/quits his application. For those old apps that run horribly on new hardware, a Virtualize Win98 is the way to go. The iPad helps revitalize and access the old applications.