VirtualBox is open-source software for virtualizing the x86 computing architecture. It acts as a hypervisor, creating a VM (virtual machine) where the user can run another OS (operating system).
The “host” OS is the operating system on which VirtualBox runs. The “guest” OS is the operating system that runs in the virtual machine. VirtualBox can run on Windows, Linux, or macOS as its host operating system.
When configuring a virtual machine, the user can define how many CPU cores the VM should have, as well as how much RAM and disk space it should have. The VM can be “paused” while it is operating. At that point, the system’s execution is paused, and the user can resume utilizing it later.
Advantage of Using Virtual Box
- Running multiple operating systems simultaneously. Oracle VM VirtualBox enables you to run more than one OS at a time. This way, you can run software written for one OS on another, such as Windows software on Linux or a Mac, without having to reboot to use it. Since you can configure what kinds of virtual hardware should be presented to each such OS, you can install an old OS such as DOS or OS/2 even if your real computer’s hardware is no longer supported by that OS.
- Testing and disaster recovery. Once installed, a virtual machine and its virtual hard disks can be considered a container that can be arbitrarily frozen, woken up, copied, backed up, and transported between hosts.
Reference:
https://www.virtualbox.org/manual/ch01.html
https://www.computerhope.com/jargon/v/virtualbox.htm