Qemu 0.15

32 bit

deb for Ubuntu
deb for Debian
rpm for openSuse

64 bit

deb for Ubuntu
deb for Debian
rpm for openSuse

Qemu is a processor emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port on new host CPU architectures.

In conjunction with CPU emulation, it also provides a set of device models, allowing it to run a variety of unmodified guest operating systems, thus it can be viewed as a hosted virtual machine monitor. It also provides an accelerated mode for supporting a mixture of binary translation (for kernel code) and native execution (for user code), in the same fashion as VMware Workstation and Microsoft Virtual PC.

Qemu can also be used purely for CPU emulation for user level processes; in this mode of operation it is most similar to valgrind.

QEMU has two operating modes:

User mode emulation:

QEMU can launch Linux or Darwin/Mac OS X processes compiled for one CPU on another CPU. Target OS system calls are thunked for endianness and 32/64 bit mismatches. Wine windows API reimplementation and DOSEMU are the main targets for QEMU in user mode emulation. This mode also allows to ease cross-compilation and cross-debugging.

Complete Computer System mode emulation:

QEMU emulates a full computer system, including a processor and various peripherals. It can be used to provide virtual hosting of several virtual computers on a single computer. QEMU can boot many guest operating systems, including Linux, Solaris, Microsoft Windows, DOS, and BSD;
it supports emulating several hardware platforms, including x86, AMD64, Alpha, MIPS, and SPARC.

Features:

* Supports emulating IA-32 (x86) PCs, AMD64 PCs, MIPS R4000, Sun's SPARC sun4m, Sun's SPARC sun4u, ARM development boards (Integrator/CP and Versatile/PB), SH4 SHIX board, PowerPC (PReP and Power Macintosh), and ETRAX CRIS architectures.
* Support for other architectures in both host and emulated systems (see homepage for complete list).
* Increased speed — some applications can run in close to real time.
* Implements Copy-On-Write disk image formats. You can declare a multi-gigabyte virtual drive, the disk image will only be as large as what is actually used.
* Also implements overlay images. You can keep a snapshot of the guest system, and write changes to a separate image file. If the guest system breaks, it's simple to roll back to the snapshot.
* Support for running Linux binaries for other architectures.
* Can save and restore the state of the machine (programs running, etc.).
* Virtual network card emulation.
* SMP support.
* Guest OS does not need to be modified/patched
* Performance is improved when the KQEMU kernel module is used.
* Command line tools allow a full control of QEMU without having to run X11.
* Remote control of emulated machine via integrated VNC server
* USB tablet support — this provides "grabless" mouse control. Activated with "-usb -usbdevice tablet".

Fabrice Bellard also wrote a Linux kernel module (with preliminary ports to FreeBSD and Windows) named KQEMU or QEMU Accelerator, which notably speeds up i386 emulation on i386 platforms.
This is accomplished by running user mode code directly on the host computer's CPU, and using processor and peripheral emulation only for kernel mode and real mode code. KQEMU also supports a kernel emulation mode in which portions of kernel mode code run on the host's CPU.

Screenshot