This page remains available mainly as an historical document

Most or all of the features are no longer available via the CDS/DL website since provision of the EPSRC UK national Chemical Database Service has been taken over by the Royal Society of Chemistry from 1st January 2013.

Some related features may be available via the RSC/CSD portal. For details of what is currently available on the CDS/DL website and also links to the RSC/CDS portal follow the link to the CDS/DL Homepage.

The information below was produced before January 2013 and may be incorrect at the present time.

Accessing the CDS using X-Windows

A number of important component facilities within the CDS require X-Windows to be installed on your workstation. For instance, you need X-Windows to access the Cambridge crystallography database via ConQuest (and associated components) and also to use the PeakQuest powder diffraction system.

X-Windows Overview

To use the components mentioned above you need to logon with your username to the main CDS server ( using "secure shell" mechanisms.

Our recommendation for configuring your X-Windows system is to use "X11 forwarding". Details are give on our Secure Shell webpage. However, if that option is not available to you scroll to the end of this page for details of alternative methods.

X-Server emulators

As indicated above Unix/Linux and Mac OSX should come with X11 already installed. If you have a Mac OSX system without X11 it is available for download from Apple [eXodus is an option for older Macs (OS8 or 9)].

Our current recommendations for Windows PCs are Exceed (where you have an HEI site licence) or Xming (free software) - see below.
Cygwin/X, MI/X, WinaXe and X-Win32 should also be considered if site a licence for Exceed is not available or where cost is a problem.

Open Text Exceed

This was previously known as Hummingbird Exceed (before that Vista Exceed). Recent versions add the option of Secure Shell logins and X11 forwarding.
Available to HEI sites as a CHEST deal.


Xming is a freely available X Window Server for Microsoft Windows (XP/2003/Vista/7).
Users should download the Xming-mesa version. More information about Xming and setting it up is available here.


For Macintosh PowerPC, G3, G4 or iMac .

EXodus is now available from Powerlan-USA. Now contains TunnelMate 1.0.1 Secure Shell client but only for Mac OS X. The current version is 8.0.2. An evaluation copy can be requested from Powerlan
The CHEST deal has expired but copies can be purchased for $135.


For Windows 95/98/NT4/2000/ME/XP Operating Systems.

Cygwin/X is a port of XFree86 to the Microsoft Windows family of operating systems and is available free of charge (licensed under an Open Source compliant license).
Cygwin/X consists of an X Server, X libraries, and nearly all of the standard X clients, such as xterm and xhost. A copy can be downloaded from the Cygwin site where a user guide is also available (make sure you select the 'xorg-x11-base' package from the 'X11' category).


X server available from Pexus for Windows XP/NT/2000/95/98/ME. 15 day evaluation. $19.99 for 1 year or $49.99 for non-expiring license.


For Windows PCs.

Version 5.3 includes SSH and OpenGL support. A 1 month license key can be obtained from Starnet which will enable you to evaluate X-Win32 in fully-licensed mode. After 30 days, the program will revert to a 2-hour demo mode. Full (academic) version cost $115, though other academic deals are available.

WinaXe Plus (formally X-WinPro)

For Windows PCs.

A free evaluation version is available from Labtam Finland Ltd. - operational 30 minutes per run. After 30 minutes session you need to restart WinaXe. No reinstallation needed. Priced at $90 or $100 for Plus version which includes SSH client.


For Windows

MI/X for Windows is a available at $25 (free 15 day trial) from Microimages.


For any Power Macintosh or Power Macintosh clone.

Compatible with older versions of the Macintosh Operating System 7.5 to 9.0.4. 16 MB of RAM are recommended.

A Secure Shell for XTen 6.1 package is available for download - SSH is freely distributed for non-commercial and private use only.
A demo version is available for download from Tenon. Priced at $175.

Making the connection without X11 forwarding

We recommend that you use X11 forwarding where possible. However, if this not the case there are additional commands required to establish a link with an X-Server or emulator.
When X11 forwarding is not used the CDS server ( needs to be told the address of your workstation so it can transmit data traffic relating to your X-Windows session. The command to type on connecting to the CDS server is:

     setenv DISPLAY [IP]:0
     setenv DISPLAY [IP]:0;xterm -ls -sb

where [IP] represents the Internet address of your workstation
You may need to enter "xhost" before connecting from your workstation (this gives permission to receive traffic from the CDS server).

It may make sense to seek recommendations from your local computer support people when setting up X-server emulators such as Exceed. Also feel free to contact the CDS (