Virtual Machines
In the IT industry the term “Virtual Machines” is one of the most used terms. In this article, it will briefly describe what are virtual machines, different types of virtual machines, advantages, and disadvantages of using virtual machines.
What is a Virtual Machine?
In simple words, virtual machine is a software that executes a new computer inside the original physical computer. In their end user can experience and work on another operating system with related software. At the same time there can be several virtual machines inside the same computer.
From Wikipedia:
In computing, a virtual machine is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination.
The above diagram shows the architecture when we have several virtual machines on a same physical computer. There you can find a term “Hypervisor Controller.” What is Hypervisor Controller? This is also known as Virtual Machine Monitor or VMM. It is a kind of software that allows one host computer to support many virtual machines by sharing its resources properly including memory and processing.
Did VMs came in this decade?
No, now it’s nearly six decades when the term ‘Virtual Machines’ came to the industry. The virtual machine using aroused in the early 1960’s at a project in IBM Yorktown Research Centre. After that virtualization is rapidly developing and today it has become one of the key technologies.
Types of Virtual Machines
There are mainly two types of virtual machines.
1. System Virtual Machines — Hardware Virtual Machines
This provides an environment with the execution of separate complete operating system. Ex: VMWare, VirtualBox
2. Process Virtual Machines — Application Virtual Machines
This provides platform independent programming environment that abstract away details of the underlying hardware from software. Ex: .NET Framework, Java Virtual Machine
Advantages and Disadvantages of Virtual Machines
It is very important to have an idea about the advantages and disadvantages of using the virtual machines. First, we will see what some advantages are of using virtual machines.
· We can run multiple operating systems in one physical computer.
· Reduces hardware costs.
· Easy to manage and maintain.
·It provides disaster recovery and application provisioning options.
Here are some disadvantages of using virtual machines.
· When there are several virtual machines on single host it may cause some unstable performances
· Sometimes it is slow and less efficient than an actual machine.
· Difficult to direct access hardware
Some other uses of Virtual Machines
· We can try new operating system without buying a new computer.
· We can test applications or software.
· Use old apps and software.
This is a brief discussion about the virtual machines. Now a days most companies create virtual machines on cloud platforms because of the advantages of having their virtual machines on cloud platforms. Almost all the cloud vendors provide the facilities to create and manage virtual machines in the cloud platforms easily. In my next article I hope to discuss about Virtual Machines on Azure Cloud Platform. Hope you have gained some knowledge from this article.
