What is Partial Virtualization?

In Partial virtualization multiple instances of an underlying hardware environment are simulated. It is not mandatory that in para virtualization, it simulates hardware. It may provide an API, which can be exceptionally used by altering the guest operating systems. Including this, it has provided various dexterous virtual machines that are compatible to several important applications. In simpler terms, it connotes that the entire operating system cannot run on the Virtual Machine as in case of full virtualization in which many applications can run.

Address space virtualization is one of the forms of partial virtualization, wherein each virtual machine comprises of a dedicated address space. This technology is often considered as an important milestone in the path of full virtualization. Partial virtualization technique was applied on the IBM M44/44X experimental paging system, first-generation time-sharing system CTSS, and systems like MVS and the Commodore 64. It very well confabulates that any OS with specific address spaces for individual users or processes, does not fall in the category of virtual machine systems.

The obligations and user experience with Partial virtualization has led to the development of the first full virtualization system. When compared on ease to impellent, Partial virtualization comes before full virtualization.

For sharing computer resources among multiple users, this technique has provided successful results. When the partial virtualization is compared with full virtualization, its demerit is that in certain situations it requires portability and backward compatibility.

Difference between Partial Virtualization and Full Virtualization

What are the Different Types of Virtualization?

Virtualization is primarily of five types –

Desktop Virtualization – In desktop virtualization, one OS (operating system) is run over another OS. For example, a Windows 7 virtual machine running over Windows XP PC.

Application Virtualization – Application virtualization allows software and other apps to be incorporated into a “single and executable” package that can be run anywhere. So with application virtualization, the apps will run in sandboxed from the OS, even though they may look like the app has changed the registry settings.

Storage Virtualization – Storage virtualization is when you group several physical resource and make it look like a single storage. The combined storage can then be further divided when required.

Network Virtualization – In network virtualization, a virtual network is decoupled from the main network. This means, there can exist several networks that will use the same network hardware.

Server Virtualization – Like every other virtualization, the virtualization of server is the process of creating several servers that behave independently despite sharing the same underlying hardware.

These are not the level of virtualization but only its types. Depending upon how isolated the virtual servers/storage/network/application instances are from the sibling VMs, virtualization can be of following levels –

Instruction Set Architecture Level – The instruction set virtualization interprets codes which were originally written for different hardware. These codes are typically run on a VM (virtual machine) through instruction set architecture.

Hardware Abstraction Level (HAL) – The hardware abstraction level is perhaps the highest virtualization achievable in theory. The HAL manages hardware using a bare hypervisor. Any virtual machine running with this technique is practically unaware of existence of other machines.

OS Level Virtualization - The OS level creates an abstract layer between apps and the underlying OS. The OS-level virtualization is achieved by running one operating system over another operating system. The host OS is, at all times, aware of the existence of a guest OS. The host takes care of the hardware and assigns resources to the guest like every other app.

Application Level – The application level allows you to run single executable program that can work anywhere like a standalone app.

Library Level Virtualization – Some application program interfaces prefer library level because OS system calls are somewhat lengthy and cumbersome. 

Partial Virtualization in Cloud Computing

The role of partial virtualization in cloud computing is crucial. First, it is only due to virtualization that a technology like the cloud exists. Second, virtualization also allows segregation of users based on their websites. Means, clouds allow clients to work as if they had their own private server. This is achievable because virtualization treats different VM instances differently.

For example, if there are ten users hosted on a single server, they will continue to enjoy the hosting environ like dedicated server. The idea is to have several virtual server on a shared platform.