Sun Microsystems (Oracle VirtualBox)

Sun Microsystems' VirtualBox, now owned by Oracle, is a software tool that allows a computer to run multiple operating systems simultaneously. For example, it lets you run Windows on a Mac or Linux on a Windows PC without restarting. VirtualBox creates a virtual environment—called a virtual machine—within your main system, providing a safe and isolated space to test new software, run different applications, or develop across platforms. It's useful for developers, testers, and anyone needing flexibility in managing multiple operating systems on a single physical machine.