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Linux Unified Kernel
UnifiedKernel 0.2.1-KingSoft WPS.jpg
LUK 0.2.1 running Kingsoft Office
Developer(s) Insigma Technology
Initial release 2006
Stable release / August 31, 2009; 6 month(s) ago (2009-08-31)
Written in C
Operating system Unix-like
Type Kernel
License GNU General Public License version 2

Linux Unified Kernel, also known as Longene[1] and informally as LUK, is an operating system kernel intended to be binary-compatible with application software and device drivers made for Microsoft Windows and Linux.[2] In order to accomplish this, key features of the Windows kernel are ported to the Linux kernel.

Longene is written in the C programming language and is free and open source software. It is licensed under the terms of the GNU General Public License version 2 (GPLv2). [3] Although the project is in the alpha stage of development as of 2009, many Windows programs already work well.



Longene aims to add all Windows kernel mechanisms, including system calls, Windows Registry, Windows Driver Model, Deferred Procedure Call, and others, into the Linux kernel to form a new kernel. The new kernel will allow both Linux and Windows applications and device drivers to work without virtualization or emulation.

In order to prevent bloating, if a function is available in both the ReactOS and Linux kernel, the Linux implementation is used. Functions are implemented using Linux loadable kernel modules, so they can be loaded and unloaded easily.

Longene has two sets of system calls and their corresponding tables: a Windows syscall set and a Linux syscall set. Windows applications call the syscall table via software interrupt "int 0x2e". Linux applications call the syscall table via "int 0x80".

The Linux Unified Kernel project does not develop the Windows and the Linux userland libraries. Those libraries are offered by others projects, such as Wine, ReactOS, and GNU.


In September 2005, the Linux Unified Kernel project gained sponsorship from Insigma Technology, a China-based IT consulting corporation.[4] The project leader, Decao Mao, proposed the idea and route of the Linux Unified Kernel.[5] He wrote a series of articles about the market, the intellectual property rights[6][7] and the techniques to explain why people needed the project and how to implement the Linux Unified Kernel. The articles Mao wrote were then compiled to form the white paper of the project.[8]

According to the white paper, to implement the Linux Unified Kernel one needs to add several parts to the Linux kernel:

  • A framework that matches the properties and requirements of Windows device drivers (i.e., the Windows device driver framework) so that multiple Windows device driver modules may be loaded into the kernel, while retaining their relationship and running conditions as in Windows.
  • A set of export functions defined by Windows kernel export function interface (WDK). To device driver programs, these functions are like library functions provided by kernel.
  • Windows native API. Microsoft did not open their native API, but "Windows NT/2000 Native API Reference" and other materials have unveiled this information. Implementing the Windows system API in the Linux kernel could be compared to the implementation of a high level language in assembly, because inside the kernel usable functions are not implemented by the external Linux kernel API anymore but by internal Linux kernel functions.

The Linux Unified Kernel project produces patches for the Linux kernel to accomplish its goal. The project developers expect these patches to eventually merge into the Linux kernel main tree.[citation needed] Those who program on the Windows platform would then be able to develop applications and device drivers for the Linux platform or port their products to Linux platform with a low cost.


Development strategy

Longene uses Wine as a base for implementing the Windows API. The project re-implements Wine's modules for use as part of the joint kernel. Longene defers from using Wine modules that have not been sufficiently implemented for the project. Versions of Longene are released when several of the Wine modules have been successfully implemented into the kernel. The new stable version will then be used as a base for implementing future modules. Windows API that have not been implemented by Wine are developed into modules from scratch.

For device drivers, Longene imports NDISWrapper into the kernel. Modifications are made to NDISwrapper for missing functionality of the Windows Driver Model using ReactOS code as a reference. The Windows Driver Kit implementation is based on ReactOS code. It uses a combination of redirecting drivers to Linux kernel resources and additional libraries that implement functions that cannot be implemented in Linux.

Release history

An early version of Longene, known as unifiedkernel-2.6.13, was released on February 15, 2006. This release had an initial implementation of the Windows system call mechanism along with a prototype for using Windows system call functions.[citation needed] The following versions have subsequently been released:

Color Meaning
Red Release no longer supported
Green Release still supported
Blue Future release
System Version Release Date Release Information
0.1.0 30 April 2006
  • kernel-win32 ported
  • Windows system call mechanism based on "int 2e"
0.2.0 31 December 2006
  • Windows Process/Thread creating implemented
  • partial implementation of Windows APC mechanism
0.2.1 04 February 2008
  • Windows Process/Thread management
  • virtual memory management
  • synchronization
  • object management
  • built-in EXE loading function
0.2.2 31 October 2008
  • Token mechanism
  • GUI installation program
0.2.2-1 17 December 2008
  • bug fixes
0.2.3 12 February 2009
  • Windows registry mechanism ported from Wine
0.2.4 22 May 2009
  • file system management ported from Wine
  • partial implementation of registry management APIs
  • binary packages for popular distributions provided 31 August 2009
  • based on Linux Kernel 2.6.30
  • support of new file systems (ext4 and others)
0.2.5 April 2010
  • move all functions of wineserver into kernel space and get rid of wineserver

Current and future development

Developers are currently working on moving all functions of wineserver into kernel space. The next version will get rid of wineserver, but Luk still depends on wine's dll files to run. And the developers are also working hard on the stabilization of SMP [9] and porting NDISWrapper code to the project.

The project's aim is a series of patches for the Linux kernel. The development team expects those patches to eventually merge into the Linux kernel main tree. In order to achieve this, developers are reducing the modifications to the main parts of the Linux kernel by moving code to loadable kernel modules.

In the future the following will be added:

  • The WDM device driver framework
  • System calls of the file system management
  • APIs in registry management
  • Various system call functions on the Windows system call interface
  • The Windows DPC mechanism
  • Exported kernel functions defined by Windows DDK

Architecture support

The Loongson 3 port is expected to utilize new instructions for Hardware-assisted x86 emulation.

Longene can also be run on software which emulates or virtualizes the above hardware, such as VMware and VirtualBox.

Available Open Source resources

The Linux Unified Kernel is based on the Linux kernel. It implements its functions in the Linux loadable kernel modules (LKMs). As opposed to ReactOS implementing functions from scratch, Longene exploits the abundant code and documentation of the Linux kernel to generate its functions. These are the main approaches to implementing the Windows mechanisms in Longene:
  1. System call interface — Some can be grafted to the appropriate Linux system calls, or partially reuse the code from corresponding Linux system calls, and the remnants have no counterpart in Linux require to use low-level Linux kernel functions to implement.
  2. Device driver framework — The device driver interrupt service register grafted to the Linux interrupt mechanism, the device drivers are concerned about running Windows kernel is mapped to the Linux kernel running on. Device driver will request DPC grafted into Linux-bh function mechanism.
  3. The Microsoft Windows native system files that are copyrighted by Microsoft — The category of .sys modules used for standard, basic, common external devices, such as disk, USB, graphics devices, network equipment and so on, there are corresponding functions in the Linux kernel. To drive those devices, it is only required to build a bridge and there is no need to create .sys modules. For the category of .sys modules that can not find the corresponding objects in the Linux kernel, emulation is required.
  4. Windows DDK — The majority of device driver interface function (as well as the data structure) have a counterpart in the Linux kernel. Some function in the Linux kernel does not correspond to relatively close objects, then use Linux kernel stuff to be built all kinds of material. The concrete approaches are, some resources calls and references can be mapped (redirect)/grafted (adapter) the Linux kernel on the counterpart, and the remnants required to realize.
ReactOS is a clone of MS Windows written from scratch. LUK uses ReactOS code as a reference to implement some basic mechanisms of the Microsoft Windows Operating System. That involves implementing the Windows device driver framework, NDIS, the system call interface, the process management and resource management, the device driver interface (Environment), etc.
Wine implements a compatibility layer, providing alternative implementations of the DLLs that Windows programs call, and processes to substitute for the Windows NT kernel. As opposed to LUK using the microkernel functions to implement Windows API in kernel space, Wine uses the macro host OS API to implement Windows API in userspace. LUK offers the Windows Process management, Thread management, Object management, etc., in kernel; Wine offers those by wineserver running in userspace.
LUK depends on Wine for the user libraries (the .dll files). Most of Wine's DLLs can be used directly by LUK. Wine code (such as the Windows Registry table) can be referred to to implement some functions. In the transitional state, LUK uses Wine to offer those functions that have not been completed yet.
Kernel-Win32 is a project intended to move some functions from the Wineserver into the Linux kernel to accelerate Wine. LUK project ported (and partly re-implemented) kernel-win32 into LUK to implement the Windows system call mechanism.
NDISWrapper recreated a partial Windows NT kernel inside a Linux kernel module, making it possible to execute modern Windows drivers inside the NT kernel box. NDISWrapper consists of a NTOSKRNL API, a basic WDM controller, and a set of Windows call wrappers such as Wireless/NDIS/USB/PnP to Linux APIs. NDISWrapper is not limited to executing only NDIS drivers; other WDM drivers can be used as long as the driver doesn't call unimplemented Windows API functions. The opening gambit of WDM of LUK will be to import NDISWrapper into LUK. Then the LUK project team implements its WDM via modifying NDISwrapper and adding functions into NDISWrapper with ReactOS code as a reference.


  • MagicLinux — MagicLinux is a Chinese Linux distribution based on Red Hat Linux. Version 2.1 of MagicLinux, released on Dec 15 2008, includes a main version (DVD, with Linux kernel, a compact version (CD, with Linux kernel and a LUK version (CD, with LUK 0.2.2).[10]And the lastest version of MagicLinux, MagicLinux 2.5 rc2, includes LUK [11]

Hardware requirements

The minimum hardware requirements to run are:

  • IA-32 processor
  • 128MB RAM
  • IDE or SATA harddisk
  • VGA compatible video card
  • Standard (PS/2 or USB) keyboard
  • PS/2 compatible mouse or Microsoft Mouse compatible serial mouse

See also


External links


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