ReactOS 0.4.16 ships graphical installer, new ATA driver and Wine 10 sync

Graphical installer and a single image

The ReactOS project has released version 0.4.16, wrapping up roughly a year and a half of development with a new graphical installer, a merged live-and-install image, and substantial rework of its video, audio, networking and storage stacks.

According to the project's release announcement, which surfaced on the Hacker News front page, ReactOS historically offered two downloads: a live CD for testing the system in a read-only environment, and a boot CD for installing to disk through a text-based installer. In 0.4.16 those are combined into a single image that can boot a live session or install to the hard disk, with the new graphical installer handling setup, basic partition management and file copying. The announcement credits Hermès Bélusca-Maïto with the work, which he documented in a series of blog posts during 2023 covering setupapi syncing and partitioning UI.

Video stack fixes

The announcement describes years of driver trouble across the major GPU vendors. A long-running Nvidia slowdown was eventually traced by Justin Miller to the kernel running out of system page table entries when loading third-party drivers — a limitation most visible with graphics drivers, which allocate more memory than most. Changing the memory manager's layout to increase available system PTEs fixed the bug.

On AMD hardware, OpenGL windows rendered blank; that was resolved by rewriting ExtEscape, based on a patch from the late core developer James Tabor. The announcement notes this builds on groundwork laid during the 0.4.15 cycle by Hervé Poussineau, including multi-monitor support and fallback to a VGA driver when display drivers fail to load, along with further stability and resource-handling fixes in win32k.sys.

Audio rebuilt around a new bus driver

HD Audio support was previously incomplete: the announcement says the old hdaudbus.sys bus driver, originally written by Johannes Anderwald, was never finished and frequently caused bugchecks when installing HD audio controller drivers. Core developer Oleg Dubinskiy imported sklhdaudbus as a replacement, and the project now expects HD audio controllers compatible with Windows XP and Windows Server 2003 to work.

The new driver depends on the Kernel Mode Driver Framework, which Microsoft open-sourced in its Windows-Driver-Frameworks repository; Justin Miller imported KMDF into ReactOS, which the project says opens the door to porting or developing further drivers against it. Dubinskiy also fixed the volume and balance sliders in Sound Properties and the Audio Volume Mixer so levels are saved and restored across reboots with HD audio codecs, extended audio device enumeration to support more sound cards, and improved binary compatibility with the Windows audio stack through Plug and Play and SetupAPI fixes.

Storage and networking

Since 2009 ReactOS relied on the UniATA driver for SATA, AHCI and support for partitions larger than 8GB. The announcement blames UniATA for slow boot times and for failing to load on many devices, producing the INACCESSIBLE_BOOT_DEVICE (0x7B) bugcheck. Contributor Dmitry Borisov wrote a new ATA driver that lets ReactOS boot in far more environments, including Hyper-V Generation 1 virtual machines.

Doug Lyons fixed the FAT chkdsk routines that broke when Microsoft's open-source FastFAT driver was imported in 2021, and Mark Jansen added a disk cleanup utility compatible with extensions written for the Windows equivalent. On the networking side, the DC21X4 adapter driver introduced during 0.4.15 gives devices with DECchip 21x4-based adapters — and guests in Microsoft Virtual PC 2007 and Hyper-V Generation 1 — working network and internet access. 0.4.16 also adds asynchronous connection support, improving networking performance and compatibility with applications that assume those APIs are always present.

Server Core and the Wine 10 sync

Core developer Carl Bialorucki added a Server Core installation type, which disables the graphical explorer shell but otherwise loads the full Win32 subsystem — comparable to the Server Core option Microsoft introduced with Windows Server 2008. The project frames it as part of an effort to see ReactOS used more widely in server and embedded environments.

ReactOS also carries a fork of Wine that interfaces directly with its Windows-like kernel rather than translating calls to a Unix-like system. For years the fork was stuck on Wine 2.x and 3.x because the project adhered strictly to Windows Server 2003 API compatibility. That constraint was abandoned late in the 0.4.15 cycle, allowing a gradual update toward Wine 10.0; the migration is still in progress but a significant portion landed in 0.4.16, and the project expects moving to Wine 11.0 or later to be considerably easier as a result.

Why it matters

ReactOS is an effort to build a free, binary-compatible Windows replacement from scratch, and 0.4.16 addresses the failures that would stop most users first: boot device errors, blank OpenGL windows, buggy HD audio and a text-mode installer. The KMDF import and the Wine 10 sync both lower the cost of reusing upstream driver and API work, which matters enormously for a project reconstructing an entire ecosystem. Dropping strict Windows Server 2003 fidelity is arguably the strategic shift here — it trades a fixed compatibility target for access to years of accumulated upstream fixes.