What is ReactOS?

ReactOS is a project, based in Mordovia, Russian Federation, to create an x86 32-bit OS compatible with the Windows NT kernel, DOS, OS/2 and Java subsystems.

By ROSHelper — Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=67644888

For the past 16 years, ReactOS has remained in alpha. The current version 0.4.14 was released on 04/10/2020. According to its developing group, this OS is 93.8% complete.

ReactOS can run older Windows software without major glitches. If you get programs from Application Manager (repository), do not upgrade them to the latest version from the vendor's website as they might break the OS. Although it reports NT 5.2 (Build 3790 SP 2) on FAT32 (not NTFS) it fails to run some newer applications — almost a game of trial and error.

For example, the latest version of Firefox available for this build is 48 Extended Support Release (08/24/2016) and 78 ESR (latest version, 06/30/2020) would not run. I had to reinstall 48 ESR to what the installer considered an upgrade the newer version of Firefox although it was clearly a downgrade.

Unfortunately, I have not been able to run emulators for any video game platforms like SNES (sorry, but if no Zelda, why bother) that I have not been able to run due to failure to install missing libraries. Maybe I could install DOS versions of these emulators.

Being a Windows clone, it uses the same mentality in naming convention and system variables as Windows. This meant that I had to change the environment variables for TEMP and TMP to C:\TEMP (bad habit that I picked up working with DOS with Windows 3.1.1). This way all temporary files (junk data) are stored in one subdirectory so I can delete them quickly. I do the same to every Windows machine that I have worked with ever since.

Although I have played with ReactOS on and off since 2014 (around version 0.3.16), ReactOS is clearly not ready for prime time. I have never used it as my main OS due to the limitation of programs that the OS can run. Do not get me wrong. I have had lots of fun with ReactOS even running a game engine, which I considered promising. As such, I do not know what else to do with it. I do not play with it as much, but I am still curious about its capabilities as a Windows replacement especially for older machines — most likely involving people and companies on a tight budget.

ReactOS relies on Wine for compatibility with the Windows NT kernel. This is similar to what Unix-like operating systems do when running a Windows-only application. This might be its weakest point of the OS although it is a quick way to achieve the goal of making a drop-in replacement for Windows.

Although ReactOS uses Wine, it is not Unix-like OS. This project is, for lack of a better legal expression, a Windows clone without reusing any of Microsoft's proprietary code that could be used in a fairly new hardware. To make sure the latter remains true, internal audits check the code (mostly C++) constantly. Redistributable packages and libraries by Microsoft can be installed on ReactOS.

ReactOS comes with a descent set of console commands in it command prompt (CMD.EXE), most of which are copies of those in Windows.

? — List all available commands (without description).
ALIAS — Sets, removes or shows aliases.
ATTRIB — Displays or changes file attributes.
BEEP — Beep the speaker.
CALL — Calls one batch program from another.
CD — Displays the name of or changes the current directory.
CHCP — Displays or sets the active code page number.
CHOICE — Waits for the user to choose one of a set of choices.
CLS — Clears the screen.
CMD — Starts a new instance of the ReactOS command interpreter.
COLOR — Sets the default console foreground and background colors.
COPY — Copies one or more files to another location.
DATE — Displays or sets the date.
DELETE — Deletes one or more files.
DIR — Displays a list of files and subdirectories in a directory.
ECHO — Displays messages, or turns command echoing on or off.
ERASE — Deletes one or more files.
EXIT — Quits the CMD.EXE program (command interpreter).
FOR — Runs a specified command for each file in a set of files.
FREE — (free) disc space.
GOTO — Directs the ReactOS command interpreter to a labeled line in a batch program.
HELP — Provides Help information for ReactOS commands.
HISTORY — Lists all commands which have been used.
IF — Performs conditional processing in batch programs.
LABEL — Creates, changes, or deletes the volume label of a disk.
MD — Creates a directory.
MKDIR — Creates a directory.
MKLINK — Creates a filesystem link object.
MOVE — Moves one or more files from one directory to another directory.
PATH — Displays or sets a search path for executable files.
PAUSE — Suspends processing of a batch file and displays a message.
POPD — Restores the previous value of the current directory saved by PUSHD.
PROMPT — Changes the command prompt.
PUSHD — Saves the current directory then changes it.
RD — Removes a directory.
REM — Records comments (remarks) in batch files.
REN — Renames a file or files.
RENAME — Renames a file or files.
REPLACE — Replaces files.
RMDIR — Removes a directory.
SCREEN — Move cursor and optionally print text.
SET — Displays, sets, or removes ReactOS environment variables.
SHIFT — Shifts the position of replaceable parameters in batch files.
START — Starts a separate window to run a specified program or command.
Executes command.
TIME — Displays or sets the system time.
TIMER — Allow the use of ten stopwatches.
TITLE — Sets the window title for a CMD.EXE session.
TYPE — Displays the contents of a text file.
VER — Displays the ReactOS version.
VERIFY — Tells ReactOS whether to verify that your files are written correctly to a disk.
VOL — Displays a disk volume label and serial number.

Keep in mind that, although ReactOS is a functional OS, it is still in alpha. It could still be considered a proof of concept, an experiment of sorts. As such, it feels fairly buggy, and somewhat outdated. Unless you need to run a program or video games) that Windows no longer supports or can run, ReactOS might not be for you.

Installing ReactOS:

Like most operating systems nowadays, the installation of ReactOS is handled by a live .ISO that can be burned to a USB drive. The installation is similar to that of Windows including the dialog boxes. I installed ReactOS in a VDI as I no longer have a physical computer lab at home.

Although I had installed and used ReactOS many times before, version 0.4.13 (currently running 0.4.14) gave me some issues when using VirtualBox running on Linux. The folks at the forum helped me troubleshoot the errors I was getting — freezing the host computer and being forced to reboot it manually. I was advised to select at least Windows 2003 (32-bit) using no more than 1 GB of RAM.

If you decide to use a VDI, you might get errors indicating that some drivers are missing. Some of these errors do not tell you what is missing and/or needed merely displaying that it needs a driver for a system device. If you run ReactOS as the sole OS in a computer or shared in a separate partition, you might need to manually install AC97 (Audio Codec '97 developed by Intel Architecture Labs in 1997, available in the Application Manager) for audio and other drivers including your 802.11 adapter.