Table of contents

Overview

This document is intended to provide you with advice on how to configure the use of X-Windows between an emulator instance (either Tru64 or OpenVMS) and it’s Windows or Linux host.

Prerequisites

• Familiarity with X11

• Familiarity with the guest operating system (Tru64 or OpenVMS)

• Familiarity with the CHARON-AXP product

Conditions and Limitations

• The X-server configurations described in this document were tested using the VcXsrv X-server on Windows.

• The guest operating system versions tested were: Tru64 V4.0F/V5.1B, OpenVMS V7.1/V7.3-2

Terminology

For the purposes of this document, the following definitions apply:

Displaying Graphical Applications Over The Network

There are various ways of methods and styles when using a separate system (X11 Server System, “Host”) to display applications running on an emulator (X11 Client System, “Guest”). The first thing to decide is if the entire “desktop environment” is to be transported to the Host. The entire desktop environment means a sessions begins with a graphical login window. The user must authenticate himself using credentials associated with the Guest. After authentication, a session manager, either CDE or DECwindows/Motif is started. Transporting the entire desktop environment will be referred to henceforth as the “Desktop Environment Session” (DES).

If transporting the DES is the goal, there are three ways of doing it:

1. Initiating a desktop session from the Host using XDMCP

2. Running a command on the Guest to start a new session on the Host. This can be done from the Host remotely, using, for example, rsh

3. Configuring the Guest XDM (X Display Manager) to automatically start a session on the Host

If the DES is not to be transported to the Host, but rather only individual application windows, each application must be started on the Guest, possibly using a remote execution protocol such as rsh.

If the Host has multiple Windows screens (i.e. monitors), and you are planning to transport the DES, you must additionally decide if you want all (or some subset) of the Windows screens to appear to the Guest as one large screen, or as several screens. One large screen allows windows to span the Windows screens, and be moved anywhere within the one large logical screen. Configuring several logical screens means that applications on the Guest must explicitly be directed to screens other than the first, for example, using “<Host>:0.1” as the display target would cause the application window to be directed to the 2nd logical screen.

One LargeWindow

A DES should almost certainly be encapsulated in a single window, with or without a frame. This can be combined with XDMCP (the X11 Display Manager Control Protocol), if the Guest supports it.

SeveralWindows

Without XDMCP, each application to be run on the guest system must be started individually. This is can be done from Windows using Putty with X11 tunneling enabled, if the Guest supports SSH. If the guest is running Tru64 V4.x or OpenVMS V7.1, it will not have an ssh-daemon. You have several choices in this case:

• Use the rsh protocol to start a remote X-application. For an rsh program for Windows, see the “Links” section of the appendix.

• Use the telnet protocol to start a remote X-application

• Install my Tru64-Helpers for V4.x, which includes an SSH client and server.

Keep in mind that both rsh and telnet transmit everything, including passwords, in clear text over the network.

Security Considerations

X11 does not contain any provision for encrypting network traffic. This means you must satisfy one of the following conditions:

1. Both client and server are on a private, trusted network

2. X11 traffic flows through an encrypted tunnel, provided by SSH, for example

If you wish to use theWindows host as the X11-display for the emulator, I recommend setting up a virtual network on the Windows host using the “vmini” network driver.

You must use the “vmini” driver, because other virtual network drivers do not work with CHARON.

NOTE: be sure to disable any firewall on the virtual network devices

Host Configuration

The procedure for configuring the host depends completely on whether it is running Windows or Linux.

Linux

This part will be enhanced/described later

In principle, it should be a relatively simple matter to configure the Linux host, because X11 is currently a standard Linux component. This will change soon, though, as many Linux distributions are evaluating new windowing systems, such as Wayland (RedHat, Fedora) or Mir (Ubuntu), which may not offer X11 compatibility.

Windows (7, 2008 R2)

You will need to install an X-Server on the Windows host. There are a variety to choose from. The Free and Open Source Software (FOSS) choices include Xming, VcXsrv, and the X-Server available as a package with Cygwin. There are many commercial packages available, including Hummingbird-Exceed, Reflection-X, X-WIN32 and MKS X-Server.

FOSS X-Servers

The Cygwin, Xming, and VcXsrv servers are all based on the X-Org open-source XServer. Xming and VcXsrv in particular are very similar. Xming actually has two versions, a current version (7.5.0.77) with bug-fixes and new features, for which a donation (suggested amount: GBP 10) is required. Without making a donation, and getting a donor password, you can only download and older version (6.9.0.31) from sourceforge (http://sourceforge.net/projects/xming). VcXsrv, on the other hand, seems to be relatively current, with bug fixes and new functionality.

VcXsrv

This article will concentrate on using VcXsrv. Much will also apply to Xming, and to a certain extent, to the Cygwin server.

To install, download the Windows installer and run as “administrator”.

Configuring the Launcher

Start the VcXsrv “Xlaunch” program by clicking on Start → All Programs → VcXsrv → XLaunch.

A “Display settings” window will appear and lead you through a series of configuration screens. The first is “display settings”. There are four choices:

1. Multiple windows

2. One large window

3. Fullscreen

4. One window without titlebar