Open Source Virtualization Platforms
VirtualBox
VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers, it is also the only professional solution that is freely available as Open Source Software under the terms of the GNU General Public License (GPL).
Xen
The Xen hypervisor, the powerful open source industry standard for virtualization, offers a powerful, efficient, and secure feature set for virtualization of x86, x86_64, IA64, ARM, and other CPU architectures. It supports a wide range of guest operating systems including Windows, Linux, Solaris, and various versions of the BSD operating systems.
Cooperative Linux
Cooperative Linux, abbreviated as coLinux, is software which allows Microsoft Windows and the Linux kernel to run simultaneously in parallel on the same machine.
FreeVPS
FreeVPS is a GPL-licensed virtualization patch for the Linux kernel . FreeVPS allows the partitioning of a single server into relatively isolated Virtual Private Servers (VPSs) using operating system-level virtualization.
OpenVZ
OpenVZ is container-based virtualization for Linux. OpenVZ creates multiple secure, isolated containers (otherwise known as VEs or VPSs) on a single physical server enabling better server utilization and ensuring that applications do not conflict. Each container performs and executes exactly like a stand-alone server; a container can be rebooted independently and have root access, users, IP addresses, memory, processes, files, applications, system libraries and configuration files. For more info
Bochs
Bochs is a portable x86 and x86-64 IBM PC compatible emulator and debugger. It supports emulation of the processor(s) (including protected mode), memory, disks, display, Ethernet, BIOS and common hardware peripherals of PCs.
Open Virtual Platforms
OVPsim is a multiprocessor platform emulator that uses dynamic binary translation technology to achieve high simulation speeds. It has public APIs allowing users to create their own processor, peripheral and platform models.
PearPC
PearPC is an architecture-independent PowerPC platform emulator capable of running many PowerPC operating systems, including Mac OS X, Darwin and Linux.
KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V).
Mac-on-Linux
Mac-on-Linux is an open source virtual machine program for running Mac OS on PowerPC computers running Linux. It can also be used to run another instance of another PowerPC-based operating system
Linux On LinuxAs the name says Linux On Linux allows you to run one instance of linux inside another linux.
Linux-VServer
Linux-VServer provides virtualization for GNU/Linux systems. This is accomplished by kernel level isolation. It allows to run multiple virtual units at once. Those units are sufficiently isolated to guarantee the required security, but utilize available resources efficiently, as they run on the same kernel.
This site contains information relating to the use and development of virtual servers based on Linux-VServer. This particular virtual server model is implemented through a combination of “se
GXemul
GXemul is a framework for full-system computer architecture emulation. Several real machines have been implemented within the framework, consisting of processors (ARM, MIPS, Motorola 88K, PowerPC, and SuperH) and surrounding hardware components such as framebuffers, interrupt controllers, busses, disk controllers, and serial controllers. The emulation is working well enough to allow several unmodified “guest” operating systems to run.
Hercules emulator
The Hercules emulator is a computer program which allows software designed for IBM mainframe computers (System/370, System/390 and zSeries) to be run on other types of computer hardware: notably on low-cost personal computers. Although there are other mainframe emulators which perform a similar function, Hercules is significant in that it enables private individuals to run mainframe computer software on their own personal computers.
JPC
JPC is an x86 emulator written in pure Java. It can run on any platform that supports the Java Virtual Machine. It creates a virtual PC compatible machine that can run MS-DOS and other x86 operating systems. Programs inside JPC can run up to 20% of the native processor speed.
DOSBox
DOSBox is an emulator which emulates an IBM PC compatible computer running MS-DOS. It is intended especially for use with old PC games.
DOSEMU, alternatively rendered dosemu, is a compatibility layer software package that enables MS-DOS systems, DOS clones such as FreeDOS, and DOS software to run under Linux on x86-based PCs