Cooperative Linux
Encyclopedia
Cooperative Linux, abbreviated as coLinux, is software which allows Microsoft Windows
and the Linux kernel
to run simultaneously in parallel on the same machine.
Cooperative Linux utilizes the concept of a Cooperative Virtual Machine (CVM). In contrast to traditional VMs, the CVM shares resources that already exist in the host OS
. In traditional (host) VMs, resources are virtualized for every (guest) OS. The CVM gives both OSs complete control of the host machine while the traditional VM sets every guest OS in an unprivileged state to access the real machine.
The term "cooperative" is used to describe two entities working in parallel. In effect Cooperative Linux turns the two different operating system kernels into two big coroutine
s. Each kernel has its own complete CPU context and address space, and each kernel decides when to give control back to its partner.
However, while both kernels theoretically have full access to the real hardware, modern PC hardware is not designed to be controlled by two different operating systems at the same time. Therefore the host kernel is left in control of the real hardware and the guest kernel contains special drivers that communicate with the host and provide various important devices to the guest OS. The host can be any OS kernel that exports basic primitives that allow the Cooperative Linux portable driver to run in CPL0 mode (ring 0)
and allocate memory.
. He announced the development on 25 Jan 2004. In July 2004 he presented a paper at the Linux Symposium. The source
was released under the GNU General Public License
. Other developers have since contributed various patches and additions to the software.
, which generally work by running the guest OS in a less privileged mode than that of the host kernel, and having all resources delegated by the host kernel. In contrast, Cooperative Linux runs a specially modified Linux kernel
that is Cooperative in that it takes responsibility for not instigating race conditions, and sharing resources with the NT kernel.
The coLinux package installs a port of the Linux kernel
and a virtual network device
and can run simultaneously under a version of the Windows operating system such as Windows 2000
or Windows XP
. It does not use a virtual machine
such as VMware
.
Debian
, Ubuntu
, Fedora
and Gentoo
are especially popular with the coLinux users.
Due to the rather unusual structure of the virtual hardware, installing Linux distributions under coLinux is generally difficult. Therefore users generally use either an existing Linux installation on a real partition or ready made filesystem image distributed by the project. The filesystem images are made by a variety of methods, including taking images of a normal Linux system, finding ways to make installers run with the strange hardware, building installs up using the package manager by hand or simply upgrading existing images using tools like yum and apt
. An easier way to get an up-to-date filesystem image is to use QEMU
to install Linux and "convert" the image by stripping off the first 63 512-byte blocks as described in the coLinux wiki.
Since coLinux does not have access to native graphics hardware, X Window
or X Servers will not run under coLinux directly, but one can install an X Server under Windows, such as Cygwin/X
or Xming
and use KDE
or GNOME
and almost any other Linux application and distribution. All of these issues are fixed by using coLinux based distributions such as andLinux
, based on Ubuntu, or TopologiLinux
, based on Slackware
.
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
and the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
to run simultaneously in parallel on the same machine.
Cooperative Linux utilizes the concept of a Cooperative Virtual Machine (CVM). In contrast to traditional VMs, the CVM shares resources that already exist in the host OS
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
. In traditional (host) VMs, resources are virtualized for every (guest) OS. The CVM gives both OSs complete control of the host machine while the traditional VM sets every guest OS in an unprivileged state to access the real machine.
Overview
Coroutine
Coroutines are computer program components that generalize subroutines to allow multiple entry points for suspending and resuming execution at certain locations...
s. Each kernel has its own complete CPU context and address space, and each kernel decides when to give control back to its partner.
However, while both kernels theoretically have full access to the real hardware, modern PC hardware is not designed to be controlled by two different operating systems at the same time. Therefore the host kernel is left in control of the real hardware and the guest kernel contains special drivers that communicate with the host and provide various important devices to the guest OS. The host can be any OS kernel that exports basic primitives that allow the Cooperative Linux portable driver to run in CPL0 mode (ring 0)
Ring (computer security)
In computer science, hierarchical protection domains, often called protection rings, are a mechanism to protect data and functionality from faults and malicious behaviour . This approach is diametrically opposite to that of capability-based security.Computer operating systems provide different...
and allocate memory.
History
Dan Aloni originally started the development of Cooperative Linux based on similar work with User-mode LinuxUser-mode Linux
User-mode Linux enables multiple virtual Linux systems to run as an application within a normal Linux system...
. He announced the development on 25 Jan 2004. In July 2004 he presented a paper at the Linux Symposium. The source
Open-source software
Open-source software is computer software that is available in source code form: the source code and certain other rights normally reserved for copyright holders are provided under a software license that permits users to study, change, improve and at times also to distribute the software.Open...
was released under the GNU General Public License
GNU General Public License
The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....
. Other developers have since contributed various patches and additions to the software.
Comparisons
Cooperative Linux is significantly different from full x86 virtualizationX86 virtualization
In computing, x86 virtualization is the facility that allows multiple operating systems to simultaneously share x86 processor resources in a safe and efficient manner, a facility generically known as hardware virtualization...
, which generally work by running the guest OS in a less privileged mode than that of the host kernel, and having all resources delegated by the host kernel. In contrast, Cooperative Linux runs a specially modified Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
that is Cooperative in that it takes responsibility for not instigating race conditions, and sharing resources with the NT kernel.
Distribution
Most of the changes in the Cooperative Linux patch are on the i386 tree—the only supported architecture for Cooperative at the time of this writing. The other changes are mostly additions of virtual drivers: cobd (block device), conet (network), and cocon (console). Most of the changes in the i386 tree involve the initialization and setup code. It is a goal of the Cooperative Linux kernel design to remain as close as possible to the standalone i386 kernel, so all changes are localized and minimized as much as possible.The coLinux package installs a port of the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
and a virtual network device
Network virtualization
In computing, Network Virtualization is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network...
and can run simultaneously under a version of the Windows operating system such as Windows 2000
Windows 2000
Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...
or Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
. It does not use a virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...
such as VMware
VMware
VMware, Inc. is a company providing virtualization software founded in 1998 and based in Palo Alto, California, USA. The company was acquired by EMC Corporation in 2004, and operates as a separate software subsidiary ....
.
Debian
Debian
Debian is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes the GNU OS tools and Linux kernel, is a popular and influential...
, Ubuntu
Ubuntu (operating system)
Ubuntu is a computer operating system based on the Debian Linux distribution and distributed as free and open source software. It is named after the Southern African philosophy of Ubuntu...
, Fedora
Fedora (operating system)
Fedora is a RPM-based, general purpose collection of software, including an operating system based on the Linux kernel, developed by the community-supported Fedora Project and sponsored by Red Hat...
and Gentoo
Gentoo Linux
Gentoo Linux is a computer operating system built on top of the Linux kernel and based on the Portage package management system. It is distributed as free and open source software. Unlike a conventional software distribution, the user compiles the source code locally according to their chosen...
are especially popular with the coLinux users.
Due to the rather unusual structure of the virtual hardware, installing Linux distributions under coLinux is generally difficult. Therefore users generally use either an existing Linux installation on a real partition or ready made filesystem image distributed by the project. The filesystem images are made by a variety of methods, including taking images of a normal Linux system, finding ways to make installers run with the strange hardware, building installs up using the package manager by hand or simply upgrading existing images using tools like yum and apt
Advanced Packaging Tool
The Advanced Packaging Tool, or APT, is a free user interface that works with core libraries to handle the installation and removal of software on the Debian GNU/Linux distribution and its variants...
. An easier way to get an up-to-date filesystem image is to use QEMU
QEMU
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....
to install Linux and "convert" the image by stripping off the first 63 512-byte blocks as described in the coLinux wiki.
Since coLinux does not have access to native graphics hardware, X Window
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
or X Servers will not run under coLinux directly, but one can install an X Server under Windows, such as Cygwin/X
Cygwin/X
Cygwin/X is an implementation of the X Window System that runs under Microsoft Windows. It is part of the Cygwin project, and is installed using Cygwin's standard setup system...
or Xming
Xming
Xming is an implementation of the X Window System for Microsoft Windows operating systems, including Windows XP, Windows Server 2003, Windows Vista and Windows 7.-Features:...
and use KDE
KDE
KDE is an international free software community producing an integrated set of cross-platform applications designed to run on Linux, FreeBSD, Microsoft Windows, Solaris and Mac OS X systems...
or GNOME
GNOME
GNOME is a desktop environment and graphical user interface that runs on top of a computer operating system. It is composed entirely of free and open source software...
and almost any other Linux application and distribution. All of these issues are fixed by using coLinux based distributions such as andLinux
AndLinux
andLinux is a Ubuntu-based system using the Linux kernel designed to run a Linux environment natively on Windows systems . It is a FLOSS software being released under the GNU GPL license...
, based on Ubuntu, or TopologiLinux
Topologilinux
TopologiLinux is a free Linux distribution to be run on or inside an existing Microsoft Windows system. The main feature of TopologiLinux is that it does not require any partitioning. It is based on Slackware and coLinux...
, based on Slackware
Slackware
Slackware is a free and open source Linux-based operating system. It was one of the earliest operating systems to be built on top of the Linux kernel and is the oldest currently being maintained. Slackware was created by Patrick Volkerding of Slackware Linux, Inc. in 1993...
.
Limitations
- Does not yet support 64-bit Windows or Linux (nor utilize more than 4GB memory), but a port is under development by the community.
See also
- TopologilinuxTopologilinuxTopologiLinux is a free Linux distribution to be run on or inside an existing Microsoft Windows system. The main feature of TopologiLinux is that it does not require any partitioning. It is based on Slackware and coLinux...
, a SlackwareSlackwareSlackware is a free and open source Linux-based operating system. It was one of the earliest operating systems to be built on top of the Linux kernel and is the oldest currently being maintained. Slackware was created by Patrick Volkerding of Slackware Linux, Inc. in 1993...
-based coLinux distribution - andLinuxAndLinuxandLinux is a Ubuntu-based system using the Linux kernel designed to run a Linux environment natively on Windows systems . It is a FLOSS software being released under the GNU GPL license...
, a UbuntuUbuntu (operating system)Ubuntu is a computer operating system based on the Debian Linux distribution and distributed as free and open source software. It is named after the Southern African philosophy of Ubuntu...
-based coLinux distrbution - Platform virtualization
- Comparison of platform virtual machines
- CygwinCygwinCygwin is a Unix-like environment and command-line interface for Microsoft Windows. Cygwin provides native integration of Windows-based applications, data, and other system resources with applications, software tools, and data of the Unix-like environment...
- MSYS
- Wubi (installer)
External links
- coLinux Home page
- coLinux Sourceforge page
- coLinux Wiki
- Virtualization with coLinux a developerWorks by M. Tim Jones
- speedLinux