I/O Communications module  
   Provides access to devices on a PCs serial and parallel port. (trial version)
   http://www.jspayne.com/io/io.html

NT Kernel Resources  
   Windows Packet Filter Kit for developing filtering/modifying communication applications. Also Windows 2000 undocumented kernel structures. Open source TDI firewall.
   http://www.ntkernel.com/

Jungo  
   Provides WinDriver and KernelDriver, device driver development tools, for Windows,Linux,Solaris.
   http://www.jungo.com/

Sybera  
   Toolkits, custom development, and training for Windows kernel driver development. Content in German and English.
   http://www.sybera.com/

2d3D, Inc.  
   Device driver and embedded development.
   http://www.2d3d.com/

Unified IO  
   C++ interface for industrial IO cards. An alternative to device drivers provided by hardware vendors.
   http://www.bbdsoft.com/interface.html

Intelligraphics  
   Device driver development including display, audio, communications, digital imaging, telecom, and embedded systems software.
   http://www.intelligraphics.com/

Pulse Train Software Ltd.  
   Custom device driver development and File System filter framework for Windows NT/2000/XP.
   http://www.pulsetrainsw.com/

TVicHW32  
   A toolkits for real-time direct access to port I/O, physical memory, hardware interrupts from a Win32 application. [Shareware]
   http://www.entechtaiwan.com/tools.htm

Direct Device Programming Links  
   Links to information about programming device drivers.
   http://www.geocities.com/SiliconValley/Peaks/8600/device.html

DriverStudio  
   An integrated set of software tools for developing, debugging, tuning, testing and deploying Windows device drivers bt Compuware.
   http://www.compuware.com/products/driverstudio/

Kernel Drivers  
   Offers design, implementation and testing custom Windows filesystem and device drivers.
   http://www.kerneldrivers.com/

VGAdoc  
   Programming information for every RAMDAC, EGA, VGA, SVGA, and VESA video card made up to 1995.
   http://home.worldonline.dk/finth/

Ionific Driver Development  
   Professional device driver development for Windows, including audio, network, graphics, custom I/O and USB drivers.
   http://www.ionific.com/services/lowlevel.shtml

Windows Device Driver Blog  
   A Weblog for the development of Windows Device drivers.
   http://www.khapre.org/index.php?/driver/index

Hill Engineering Consulting  
   Specializes in the design and development of Windows, Linux and DOS device drivers and real time firmware.
   http://www.hill-eng.com/

User CONfigurable Driver (UCON)  
   Enables to quickly and easily develop communications drivers for any serial device or ethernet device. Designed as a driver plug-in, UCON is completely integrated with OPC server KEPServerEX. By Kepware Technologies.
   http://www.kepware.com/Products/products_UCON.html

Driver Maker  
   Develop drivers for Win32 platform.
   http://drivermaker.home.comcast.net/

MemAccess Library  
   Gives programmers control of hardware devices from Win32 application without using the Windows Drivers Development Kit (DDK). It allows real-time direct access to memory mapped I/O. By Zeal SoftStudio. [Shareware]
   http://www.zealsoftstudio.com/memaccess/

NTPort Library  
   Enables real-time direct access to PC I/O ports. By Zeal SoftStudio. [Shareware]
   http://www.zealsoftstudio.com/ntport/

Visual Enterprises NTIO DDK  
   Provide Visual C++ and Visual Basic developers code and tool resources for writing complicated device IO_CTL drivers.
   http://www.vcomsoft.com/DDKDOC.htm

California Software  
   Development device drivers for VxWorks, Embedded Linux and Windows CE platforms.
   http://www.cswl.com/embedded/

BSQUARE  
   Tools to build device drivers for Microsoft Windows operating systems.
   http://www.bsquare.com/

Divas Software  
   File System Driver Development for Windows based systems using IFS and Device driver development using VxWorks, Linux, WinCE.
   http://www.divassoftware.com/services/deviceDrivers.htm

Device Driver Development Resources  
   A list of selected sites, news groups and tools to help locate additional device driver resources and development tools. List also includes hardware and software resources for the target side development and for embedded systems.
   http://www.jungo.com/resource_index.html

USB Analyzer  
   A professional software-based analyzer for USB driver developers. It captures and analyzes I/O requests for all USB devices. Targets Windows platforms and USB 2.0 and 1.x.
   http://www.sourcequest.com/

Modular Systems  
   Development of device drivers for Windows, system software and .NET applications.
   http://www.modularsystems.dk

Concepts Systems  
   Windows Device Driver, Linux Kernel Programming training.
   http://www.conceptsinc.s5.com/

Device Driver Expert  
   Specializes in developing kernel-mode drivers for Windows NT, 2000, XP, including WDM, USB, and NDIS drivers.
   http://www.driverexpert.com/

VMWare's Back  
   Virtual Disk drivers for Windows to support VMWare
   http://chitchat.at.infoseek.co.jp/vmware/index.html

OSR Online  
   Device driver development information, DDK online.
   http://www.osronline.com

Beyond Logic Company  
   Documentation for writing drivers for USB devices.
   http://www.beyondlogic.org/

Matrikon OPC  
   Real-time process drivers for plant systems, including OPC clients and servers, as well as driver utilities, development tools, educational resources, and training and support services.
   http://www.matrikonopc.com/