1. Build environment
--------------------

To build the system it is strongly advised to use the ReactOS Build Environment
(RosBE). Up-to-date versions for Windows and for Unix/GNU-Linux are available
from our download page at: https://reactos.org/wiki/Build_Environment

Alternatively one can use Microsoft Visual C++ (MSVC) version 2010+, together
with separate installations of CMake and the Ninja build utility.


2. Building ReactOS
-------------------

A throughout guide for how to build ReactOS can be found at:
  https://reactos.org/wiki/Building_ReactOS

In the following we only make a quick overview.


2.1 Building the binaries

To build ReactOS run 'ninja' (without the quotes), or alternatively run
'make' if you are using the Make utility, from the top directory.
NOTE: In the other examples listed in the following, similar modification
holds if you are using the Make utility instead of Ninja.
If you are using RosBE, follow on-screen instructions.


2.2 Building a bootable CD image

To build a bootable CD image run 'ninja bootcd' (without the quotes) from the
top directory. This will create a CD image with a filename, ReactOS.iso, in
the top directory.


3. Installation
---------------

By default, ReactOS can only be installed on a machine that has a FAT16 or FAT32
partition as the active (bootable) partition. The partition on which ReactOS is
to be installed (which may or may not be the bootable partition) must also be
formatted as FAT16 or FAT32. ReactOS Setup can format the partitions if
needed.

Starting 0.4.10, ReactOS can be installed using the BtrFS file system. But
consider this as an experimental feature and thus regressions not triggered on
FAT setup may be observed.

ReactOS can be installed from the source distribution or from the bootable CD
distribution. The two ways to install ReactOS are explained below.


3.1 Installation from sources

If you don't have an existing ReactOS installation you want to upgrade, then
build a bootable CD as described above. Burn the CD image, boot from it, and
follow the instructions to install ReactOS.

If you have an existing ReactOS installation you want to upgrade, then to
install ReactOS after building it, type 'ninja install'. This will create
the directory 'reactos' in the top directory. Copy the contents of this
directory over the existing installation.

If you don't want to copy the files manually every time you run a
'ninja install', then you can specify the directory where the files are
to be copied to during installation.

Set the ROS_INSTALL environment variable. If you are on Windows this could be
done by:

  set ROS_INSTALL=c:\reactos

If you are on Linux this could be done by:

  export ROS_INSTALL=/mnt/windows/reactos

Now run 'ninja install' to install the files to the new location.


3.2 Installation from bootable CD distribution

To install ReactOS from the bootable CD distribution, extract the archive
contents. Then burn the CD image, boot from it, and follow instructions.


4. Help
-------

If you run into problems or have suggestions for making ReactOS better, please
visit the address below. Mailing lists are available for a variety of topics,
bugs should be submitted to JIRA and general chat takes place in the forums,
or #reactos on freenode.

https://reactos.org/

ReactOS Development Team