VirtualBox can be used to try out the OS (Operating System) without changing the existing OS that you use, so if you are done try new OS, you can easily remove them. The following will explain how to install Centos 7 in VirtualBox.
1. Following the initial appearance of virtualbox. On the left panel there is a list of the Virtual Machine. Virtual Machine is a virtual machine that has been installed OS, if you open virtualbox the first time, the panel will be blank. Click New to add a new Virtual Machine.
2. Please enter the name of the virtual machine, the type and version of the operating system that will be installed and than click Next.
You can specify how large the memory that will be used. Maximum use of memory is memory that is installed on your PC, don't fill the memory is too large, so that it can make your PC slow because used by VirtualBox. Here we use the memory recommendations.
You can create a virtual hard disk, or use a virtual hard disk that you created earlier.
There are many type of virtual hard disk, here we use the VDI standard type i.e. used VirtualBox.
Here I selected "Dynamically Allocated", just use the disk allocation unused. Whereas the "Fixed size" will allocate the appropriate hard disk you created.
Suppose you create a hard disk with a capacity of 50 GB, while utilised only 20 GB. On a dynamic disk, the real you will diminish his capacity 50 GB, whereas in Fixed, 20 GB will be reduced.
Specify the name of your virtual hard disk along with its size. For Centos only, 8 GB is enough.
5. Virtual Machine has been created. Now you can simply add the ISO file Centos boot for the first time.
6. Right click on the virtual machine that you created earlier, and then select "settings"
7. and then you click on "Storage"
8. Click "Controller: IDE". Then you will see a picture of the CD and then click CD images that, after that click on "Choose disk" to select the ISO file Centos.
9. Select Centos iso file in place you then save it, and then click open.
10. Then click OK
11. After that click on the virtual machine that you created earlier. Then click the "start" button to boot using Centos on a Virtual Machine that we have made.
12. Booting Centos
Then a new window will be out featuring the early booting Centos for the installation process.
13. Then you just choose to do the installation, your picky as you want.