Host Access Options

  Introduction  

We have many options in providing user access to your Unisys mainframe.  This page describes the various solutions that are available to you.

Terminal Mode Access

The most straightforward host access is provided by the QTerm desktop emulators (QTermUTS and QTermT27) or by the web browser based emulators (Web-UTS and Web-T27).

Both the desktop and browser based emulators provide the same facilities; a very rich set of functionality on top of the requisite terminal emulation, including scripting and file transfer.

The installation is painless; simply set up the required files on a network server and tell users to run the server installer or navigate a browser to the web server.

Even the "most straightforward host access" poses several implementation choices and you are best positioned to choose.  The basis for choice is technically similar to many other programs and your corporate guidelines may help out here.

• The QTerm desktop products are fully fledged executable programs that must be installed on the desktop.
  
• The web products are ActiveX controls that run inside a browser and have the significant advantage of being automatically loaded to the user's machine as required.
• You can use the ActiveUTS/ActiveT27 components inside a browser to give a very detailed level of scriptable control.
• Cross-platform support is provided by deploying the Java applets, again with the automatic loading functionality provided by a web browser.

Enhanced QTerm Access

The automation interface allows you to control QTerm from another COM-compliant program.  

If for example you had a document reader program that pulled in data from a passbook and wanted to send that data to the host in a transaction it is very straightforward to make automation calls to tell QTerm to display the data on the screen. 

Enhanced Browser Access

Our default web pages only contain the Web-UTS or Web-T27 control, in order to provide as large a screen as possible, but you can easily design your own web page containing the web control, and add buttons, information, links etc to help the user.

Session Relay

There are times when it is advantageous to configure a session relay in the network, such that all users connect to an intermediate server, where you can impose extra security, terminal pooling etc.  

For example, the AccessServer provides a secure endpoint for encryption and pooling.

Building Customized Client Access

There are situations where you may require very specialized host access.  For example you may have a set of users who are not comfortable with terminal screens, or you are not comfortable with providing them with full mainframe access.

Several potential solutions come to mind:

• Develop a Visual Basic (or C++ or C# etc) program and drop an instance of the ActiveUTS or ActiveT27 control on your form.  The control does not have to be visible.  You then use the events that are fired from the control to know when messages arrive, and then call methods to pick up the data off the virtual terminal screen.  And display this data in your VB fields.  
  
  The obvious advantage is that you can easily augment the display with standard user interface controls such as list boxes, buttons and drop down lists.
  
• For a similar effect in a web browser, place the ActiveX control in a web page and use JavaScript to customize the user interface

Advanced Protocol Solutions

When you need to access a Unisys mainframe inside the topology of a legacy network you may need special interfaces or to only user certain protocol layers.

All messages between your program and the AccessServer use a Header/Data message format.  The header identifies the terminal connection and the command.  The data is the payload to be sent to/from the host.

The ActiveUTS/ActiveT27 controls support methods and events that allow you to provide your own host transport but still use the presentation layer to interpret and display the datastream.  See the InputData and InputAttention methods in the QTermSDK details.