MKS Homepage v8.6 

MKS X/Server is designed to be the ideal solution for interoperability of PCs and UNIX/Linux systems, and provides the usability and flexibility that users as well as enterprise system administrators require. MKS X/Server is a great companion to MKS Toolkit, the leader in UNIX to Windows interoperability.

MKS Inc.
12701 Fair Lakes Circle,
Suite 350
Fairfax VA



MKS X/Server 8.6

MKS X/Server 8.6 is the latest version of MKS' newest interoperability product, MKS X/Server, a high performance X/Server for Windows environments. With this release, MKS X/Server improves performance and supports the latest standards while maximizing application compatibility and minimizing the need for specialized configurations for specific applications. For a list of fixes included in this release as well as other MKS X/Server releases, see Fixed Problems below. Details on the new features of this release can be found in the following sections:

Updated SSH/SSL

The SSH client and OpenSSL used by MKS X/Server 8.6 have been updated to the versions used by MKS Toolkit 9.5. The SSH version is OpenSSH_6.0p1. The OpenSSL version is 1.0.1c.

Full Windows 8 and Windows Server 2012 Compatibility

MKS X/Server 8.6 is the official MKS X/Server release for compatibility with Microsoft Windows 8 and Microsoft Windows Server 2012.

New Features in Previous Releases

Hardware and Software Requirements

  • Windows compatible x86 PC
    • Windows® 2000
    • Windows® XP
    • Windows® Server 2003
    • Windows® Server 2003 R2
    • Windows® Vista
    • Windows® Server 2008
    • Windows® 7
    • Windows® Server 2008 R2
    • Windows® 8
    • Windows® Server 2012 R2
  • Windows Compatible x64 PC
    • Windows® XP x64 Edition
    • Windows® Server 2003 x64 Edition
    • Windows® Server 2003 R2 x64 Edition
    • Windows® Vista x64
    • Windows® 2008 Server x64 edition
    • Windows® 7 x64
    • Windows® Server 2008 R2 x64 Edition
    • Windows® 8 x64
    • Windows® Server 2012 x64 Edition
  • Windows® Server 2003, Windows® Server 2008, and Windows® Server 2008 R2 for Itanium-based Systems are supported with the 32 bit X Server.
  • Typical installation requires 40 Mb of disk space.

Installing MKS X/Server

If you have SCO XVision Eclipse, you must uninstall it, or install MKS X/Server on another machine.

When installing MKS X/Server you must install from an account with local or domain administrator privileges. You do not need to be an Administrator, but your login ID must be a member of the local or domain Windows Administrators group before you can install.

All MKS X/Server products share a common installer. If you are installing from a CD, insert the MKS X/Server distribution CD; the installer should start automatically. If you are installing from an electronic distribution, run the self-extracting installer.

To install MKS X/Server, click the Install X/Server button and follow the instructions on the dialogs that appear.

Note: You should turn off all virus protection software before installing MKS X/Server. Such software can sometimes cause the installation to be interrupted and rolled back. Once you have installed MKS X/Server, you can turn virus protection back on.

For step-by-step installation instructions and an installation FAQ, see

Silent and Administrative Installations

For step-by-step installation instructions and information on administrative and silent installations for MKS X/Server see

Uninstalling MKS X/Server

Uninstalling MKS X/Server

To uninstall MKS X/Server, use the following procedure:

  1. From the Control Panel run Add/Remove Programs.

  2. Remove MKS X/Server.

You must reboot your system before reinstalling MKS X/Server.

Uninstalling SCO XVision Eclipse

  1. From the Control Panel run Add/Remove Programs.

  2. Remove SCO XVision Eclipse. (This is only necessary if the XVision X server is installed. This X Server was normally only installed with previous versions of MKS Toolkit for Interoperability and MKS Toolkit for Enterprise Developers.)

You must reboot your system before reinstalling MKS X/Server.

Known Issues

The following known issues exist in MKS X/Server:

  • Overlay Planes using NVIDIA Cards on Vista.
    • Currently, issues exist with using Overlay Planes on systems with NVIDIA cards running Windows Vista. To implement Overlay Planes, X11 uses two separate Win32 windows (one for the main plane and one for the overlay). Normally, Windows expects one window with two layers, so problems can result. There are two approaches to dealing with this issue.
      1. Do not initialize the main plane. This results in a GPF when NVIDIA nvogl32.dll (or nvogl64.dll) calls wglSwwapLayerBuffers().
      2. Initialize the main plane. This works on all systems except those using NVIDIA cards and running Windows Vista. On Windows Vista, the main plane of the overlay window is not transparent and is 100% black, thus obscuring the main plane behind it.
      This issue has been submitted to NVIDIA and their development group is looking into the problem as NVIDIA bug number 479862.

  • Wandering Overlay Planes with NVIDIA Cards.
    • On systems using an NVIDIA video card and running Windows XP, 2003, or Vista, moving the main window causes the overlay to wander with respect to its parent. The main window itself is not moving. However, if the display is repainted, everything is where it is supposed to be. For this reason, the overlay plane is currently hidden during such a move (when full window drag is enabled) and shown again once it reaches its destination. Once Microsoft provides a fix for this problem (Microsoft SXR081104600800), an environment variable will be available to turn this behavior on and off.

  • NuTCRACKER Platform Applications and Black Screens with NVIDIA Cards
    • When MKS X/Server is running on a system with a NVIDIA video card and has both Hardware Acceleration and Direct Rendering enabled, a request to use direct rendering from a NuTCRACKER Platform application using OpenGL results in nothing but a black screen. Disabling either Hardware Acceleration or Direct Rendering should solve the problem. NVIDIA is aware of the issue and questions about the availability of a fix should be referred to them.

  • NuTCRACKER Platform Applications and Direct Rendering
    • When direct rendering is enabled for a NuTCRACKER Platform application that uses OpenGL and an XServer is set to use Direct Rendering, there are times (very random) when the client application appears to freeze when exiting (CTRL-C does not work and you must use the kill -9 command to force it to exit). In this case, the Microsoft Win32 library OpenGL32.dll is waiting for a thread to set a variable that it never will because during DLL_PROCESS_DETACH, only one thread remains running. This has been reported to Microsoft as SRX081104600852 and appears only to be a problem when running Windows XP, Windows 2003, and Windows 2003 R2. On Windows Vista, you may see a slight delay at process exit but the process does exit.

  • Connecting to CDE on Solaris Using IPv6.
    • You must use either use an IPv4 IP address or disable IPv6 XDMCP when connecting to an IPv6-enabled Solaris system running CDE. You can disable IPv6 XDMCP by checking the Disable IPv6 on the XDMCP Advanced Settings dialog.

  • XRemote and RPS.
    • If you wish to use Remote Program Starter (RPS) to start X clients over XRemote, you must manually set the display name for the RPS command to match the XRemote proxy server display.

  • XVSpy.
    • Do not use a font server while recording an X session.

  • Terminal Emulators.
    • When using an embedded emulator in-place, only a limited implementation of the emulator toolbar support is available.
    • When using an emulator in an ActiveX document container application, the emulator's printing facilities are not available.
    • When using an embedded emulator in-place in Microsoft Word, or in an ActiveX document container application, the emulator's context help does not work.
    • To upgrade desktop VT320 applications, the VT420 emulator must be installed.

  • Vision Resume.
    • To use Vision Resume with XRemote, you must disable host access control for MKS X/Server.
    • When used with Vision Resume, Netscape might display "Sequence lost". You can safely ignore this message.
    • Some SCO UNIX X clients, such as scocal and scocolor, work with Vision Resume when MKS X/Server is using a PseudoColor display but not when it is using a TrueColor display.
      These clients will fail with third-party X servers when running with Vision Resume, unless the following lines are appended to the server's rgb.txt file (for example, /usr/lib/X11/rgb.txt):
      203 203 192            scoBackground
      11  0   113            scoForeground
      255 240 248            scoTopShadow
      255 206 137            scoActiveBackground
      43  45  49             scoActiveForeground
      254 222 255            scoActiveTopShadow
      172 186 204            scoAltBackground
      0   0   255            scoHighlight
      If you have problems starting a Resume session, ensure a link has been made between /usr/bin/xresume and /usr/local/xserver/bin/xresume
      (see the Help topic 'Configuring Vision Resume on UNIX' for more details).
    • If on starting a Resume session you see the error message "Cannot relocate your Resume session to that display" this may be caused by a network naming problem. Try displaying an X client from the UNIX host that you run the proxy server on to your Vision X Server, using the X Server's full DNS name (for example, xclock -display If this reports "Cannot open Display" then you have a naming problem—try adding the full DNS name to /etc/hosts.

  • Multiuser Windows environments.
    • MKS X/Server Printing does not work on Windows 2000 or Windows Terminal Server running in multi-user mode. You can use LPD Printing in these environments.

  • MKS X/Server 3D.
    • Restrictions
      • Backing store shouldn't be used with the GLX extension.
      • OpenGL extensions are not available.
    • Notes
      • The GLX extension is enabled by default. The GLX extension can be disabled using the MKS X/Server Configuration program.
      • If you experience problems with colors when running OpenGL applications on a 256 color display, setting the X/Server default visual class to TrueColor may improve the situation. To do this, choose:
        X/Server Properties > Color tab > Let me specify a particular default visual class.
      • Matrox Millennium video cards running in 16-bit color can prevent some OpenGL applications from running or displaying correctly. Matrox has been informed of this problem.

Customer Support

Contact MKS Toolkit customer support at:

Web Site:
Online Request Form:
Telephone: +1-703-803-7660
Fax: +1-703-803-3344

Additional MKS Interoperability Resources

There are several other sources for additional information about our MKS Interoperability products.

We have general product information, including technical specifications, detailed utility listings, and datasheets at:

We offer a resource kit including example scripts, additional utilities, more tutorials, and a wide variety of other useful information at:

We have several additional articles, tutorials, and white papers about using features of MKS Interoperability products at:

Through the years, we have accumulated a lot of technical details about the MKS Interoperability products and have put this information in a searchable database at:

Our customers commonly ask certain questions. These questions and their answers are in our Frequently Asked Questions pages at:

Known installation issues are listed at:

Fixed Problems

Several problems were fixed in MKS X/Server 8.6. These are listed at:

Fixed Problems in Previous Releases