QEMU

QEMU stands as a comprehensive, free, and open-source solution for both hardware virtualization and full system emulation. It enables users to run multiple virtual machines, each with its own private virtualized hardware (CPU, memory, storage, etc.), on a single physical host. Crucially, QEMU's emulation capabilities extend far beyond this, allowing you to run software and entire OSes built for different processor architectures. This dual nature makes it a uniquely flexible tool for software development, cross-platform testing, legacy system preservation, and educational purposes, all without any licensing cost.