Launching a 3270 emulator from Zowe Explorer

Many enterprise application development teams engaged in long-term projects have numerous tools, utilities, jobs, processes, and best practices that rely on a traditional 3270 development environment. Remote Connection Emulator (RCE) integrates traditional 3270 tools and practices into Z Open Editor through Zowe™ Explorer. It provides access to the mainframe to view unique information and mainframe tools and processes that are not available in Zowe Explorer. By using Remote Connection Emulator, you can connect to the remote system and open a full-screen emulator. Z Open Editor's RCE client is based on the same technology as the RCE client built into the IBM® Developer for z/OS® Eclipse client. See its documentation here for more information on various features and settings.

Some key features of RCE are

  • There are many personal configuration options such as color mappings, fonts, screen size, and so on.
  • Screen size adapts to browser window size.
  • Screen keyboard and personalized custom key mappings.
  • Advanced selection and "cross-hair support" for copy, cutting, and pasting text.
  • BiDi support is available, for example, for languages such as Hebrew.

Z Open Editor's RCE client depends on a web server that runs on IBM Remote System Explorer (RSE) API server. Once provisioned and configured, it can be accessed using the RSE API profile that a Z Open Editor user creates for Zowe™ Explorer. The information provided by the profile is used to authenticate and check entitlement on the RSE API server before opening the 3270 session in the user's default web browser. The action is added by Z Open Editor as a new context menu command in Zowe Explorer's tree view that enables the user to launch the 3270 emulator for a specific Zowe Explorer profile of type RSE API.

Requirements

z/OS components

  • RSE API 1.2.1 or higher, which is part of the z/OS Explorer 3.4.1 product, must be installed for the host defined in the RSE profile.
  • RSE API 1.2.2 or higher must be installed to enable support for RCE with token authentication.
  • Emulator configuration, the RSE API documentation specifies four emulator parameters that can be configured that is RCE_LUNAME, RCE_ENABLE, RCE_PORT, and RCE_SECURITY.

Client components

How to launch the emulator

Right-click an RSE profile in the Zowe Explorer tree view. The list of actions includes two emulator launch options. The first launches the emulator in a panel within VS Code. The second launches the emulator in an external web browser. When you launch in an external browser, you may be prompted to open the external website. Choose the Open option to launch the emulator. When the web page opens in the browser, a host login screen appears.

Troubleshooting

  • If the launch 3270 action does not appear in the list of actions for an RSE profile it is likely that either the IBM Z Open Editor advanced capabilities check box is not selected or Zowe Explorer is at a version older than 3.1.1.
  • If launching RCE within VS Code results in a blank RCE panel, it usually indicates a certificate issue with the host. To work around this, you can:
    • Relaunch RCE and choose to open it in an external web browser. A prompt will appear asking whether to open an external website. This prompt includes a Configure Trusted Domains button. Click this button, then select the option to trust the host and port defined in your RSE profile.
    • Start VS Code from command line or from a customized shortcut using code --ignore-certificate-errors, which disables certification enforcement in the VS Code Webview. Check with your system administrator to confirm whether this is allowed in your environment. If you are working in a test environment, such as IBM stock images with self-signed certificates provided with IBM Virtual Dev and Test for z/OS, IBM Wazi as a Service, or IBM Z Development and Test Environment, this option may be the quickest way to get RCE running. Also ensure that the RSE API server on these images uses port 992 for 3270, which is the default for the stock image but not the RSE API default.
  • The RSE API host certificate configuration can affect whether or not RCE displays in web views or browsers. If you're still seeing a blank RCE panel, check your certificate configuration and make sure it's following rules described in the RSE documentation.
  • If you receive the message CRRZG5408E The RSE API version must be 1.2.1 or higher for 3270 emulator functionality to be supported, it indicates that you must upgrade your RSE API version to 1.2.1 level or higher.
  • If you receive the message CRRZG5370E Timed out launching the 3270 emulator, or CRRZG5367E The 3270 emulator is unable to contact to the host, it indicates that a connection to the host cannot be established. Check that you have internet access to the host.
  • If you receive the message, CRRZG5371E The 3270 emulator is unable to connect to the host with the specified userid and password, it indicates that a connection to the host is established, but the userid or password is invalid. Verify that your credentials are correct.
  • If you receive the message, CRRZG5372E The 3270 emulator requires a VU license, but none is installed on the host, it indicates that the host you are connecting to does not have a VU license installed. Contact your host administrator to install the VU license.
  • If you receive the message, CRRZG5373E The 3270 emulator is disabled on the host, it indicates that the host administrator disabled remote emulator functionality. Contact your host administrator to enable this feature.
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Contributors: phaumer, Peter Moogk, Billie Simmons, PETER HAUMER, Esther M, Swathi Sadananda