The ReactOS Project is pleased to announce the release of version 0.4.9,
the latest in our accelerated cadence targeting a release every three
months.
While a consequence of this faster cycle might mean fewer headliner
changes, much of the visible effort nowadays comes in the form of
quality-of-life improvements in how ReactOS functions. At the same time
work continues on the underlying systems which provide more subtle
improvements such as greater system stability and general consistency.
Self-Hosting
============
The ability to build ReactOS on ReactOS, known as self-hosting, has
often been touted as a sort of milestone in the OS’ maturity, but the
details are far more nuanced. Compiling any large codebase, whether it
be an operating system or even a web browser, stresses the system in a
myriad of ways, with one of the biggest being memory usage and storage
I/O. Code being compiled needs to be loaded from storage into memory,
and more memory is required to hold all of the compiled objects as they
are linked together. Scheduling is also to a certain extent stressed, as
most modern build systems will attempt to spawn multiple compilation
processes to speed up the build process.
In the past, ReactOS was actually capable of self-hosting, but this
capability came with significant caveats, with the biggest being this
was achieved in a much older version of the ReactOS kernel. Since the
reworking of the kernel into a more NT-compliant design and
implementation, various gaps in functionality that remained to be
completed rendered ReactOS unable to build itself again. After many
years of hard effort, including the most recent batch of filesystem
related changes done by Pierre Schweitzer, ReactOS is once more able to
self-host. And in the spirit of open source, it was the FreeBSD
project’s implementation of qsort that helped Pierre bridge some of the
last pieces needed to achieve this.
https://reactos.org/sites/default/files/imagepicker/1249/image2.jpg
Stability
=========
A major source of system instability came from the complex interplay
between the memory manager, the common cache, the hardware abstraction
layer (HAL), and the FastFAT driver. The biggest culprit in the
instability came from the significant resource leakages caused by the
FastFAT driver, resulting in it eating up the common cache to the point
where attempts to copy large files would result in a crash. To rectify
this problem, Thomas Faber and Pierre worked together to correct the
FastFAT driver’s behavior, adding in write throttling support and
restraining its usage of the cache. While a more conservative usage of
the cache might see the system behave a bit more slowly during IO
operations, it ensures that resources remain available to service for
large IO operations instead of crashing like before.
Another notable improvement on FastFAT is the rewrite of the support for
dirty volumes greatly reducing the chance of file corruptions. Whenever
a dirty volume is been detected during boot “chkdsk” (Check Disk) will
trigger a repair on those volumes. This often can protect the system
from becoming unusable after a crash. The two images below are showing
chkdsk in action:
https://reactos.org/sites/default/files/imagepicker/1249/image4.pnghttps://reactos.org/sites/default/files/imagepicker/1249/image1.png
In addition to the work done during regular development, Joachim Henze
made a significant effort during the release candidate testing to track
down regressions and other bugs that have crept in since the last
release. It cannot be overstated just how much work such manual testing
takes, and Joachim should be applauded for his dedication and
perseverance in ensuring 0.4.9 would be the best release to date.
Shell Improvements & Features
=============================
Several quality of life improvements have come to the shell, the first
of which is a built in zipfldr (Zip Folder) extension by Mark Jansen.
While Windows has long possessed this capability, now ReactOS can also
uncompress zipped files without needing to install third-party tools to
accomplish it. And as the gif below demonstrates, ReactOS’
implementation is indeed very zippy.
https://reactos.org/sites/default/files/imagepicker/1249/image3.gif
And of course with such new extensions it would probably be useful to be
able to manage them, something that Katayama Hirofumi MZ has been
working on, along with plenty of other improvements to the shell.
Another major piece of functionality that might appear simple but is
actually quite complex is the ability to choose whether to move, copy,
or link a file or folder when you drag it with the right mouse button.
This piece was completed by Giannis Adamopoulos, whose prior work has
been so integral in making the current ReactOS shell behave and function
in ways users are long used to from Windows.
https://reactos.org/sites/default/files/imagepicker/1249/image5.gif
Other Improvements
==================
There are of course plenty of other changes in less trodden parts of
ReactOS, with many people providing contributions and improvements.
These range from the functional, like zooming no longer crashing in the
Paint application thanks to Stanislav Motylkov, to more behind the
scenes like Timo Kreuzer’s continued efforts to prepare the codebase to
actually function when building a x64 target (the project owes Timo many
bottles of beer for taking on that one).
Other quality of life improvements include a new mouse properties dialog
in the GUI component of the ReactOS installer by Eric Kohl, while Eric’s
work involving starting and stopping of services, the device manager,
and the sound mixer are more geared towards long term improvement and
functionality. Hermès Bélusca-Maïto has continued his work in what might
be termed the utilitarian applications of ReactOS, such as the clipboard
viewer, the event viewer, the log-off dialog box, and the command prompt
shell. And of course one can never forget RAPPS, the gateway program
used for getting various applications installed on ReactOS. Considering
ReactOS is intended to support many different languages, it is only
appropriate that its unicode support be a priority, something that
Alexander Shaposhnikov has lent his hand to.
Compatibility in Windows is reliant on a ShimEngine that allows the
loading of slightly different versions of libraries and APIs. ReactOS is
much the same, and Mark has added the ability for ReactOS to present
itself as Windows 8.1 with the Version APIs. As a sidenote, the engine
itself proved useful in a rather unconventional manner when it was
demonstrated to help reduce the loading time of the game Globulation 2.
Of course ReactOS is not just about the features in the here and now,
but also about preparations for the future. Thomas and Vadim Galyant
have started merging in their improvements to the USB stack in
preparation for native, official support for the oft requested booting
from such devices. We’re not there yet, but we’re getting closer with
every release.
Since the transition to GitHub, the project has also received many pull
requests from old and new contributors alike. The team offers its
sincere thanks to everyone that has taken an interest in helping improve
the project, and we look forward to meeting even more of you in the future.
Syncing third parties
=====================
ReactOS, being an open source project as well as its ecosystem, uses
several bits of other open source projects. In 0.4.9 release Amine
Khaldi has synced many user mode DLLs to WINE Staging version 3.3.
Statistics
==========
JIRA Issues fixed (this includes both bugs and improvements) - 137+
Number of commits - 922
The oldest bug fixed for 0.4.9 - https://jira.reactos.org/browse/CORE-7744
Pull requests merged - 109
0.4.9-release branch was forked from master on 2018-05-20 after
0.4.9-dev-885-gddd03a8
- Press Release: https://reactos.org/project-news/reactos-049-released
- General Notes: https://reactos.org/wiki/0.4.9
- Tests: https://reactos.org/wiki/Tests_for_0.4.9
- Changelog: https://reactos.org/wiki/ChangeLog-0.4.9
- Community Changelog: https://reactos.org/wiki/Community_Changelog-0.4.9
- Download page: https://reactos.org/download
