How to connect to a mainframe

With the pandemic, everyone has been finding ways of working from home – or, in fact, working from anywhere. It’s not that mainframers had never worked remotely before, it’s just that recently more of them needed to do it most of the time.

Probably, the best-known way to access a mainframe is to use 3270 emulation software running on a PC. Examples of this type of software are IBM’s PComm and tn3270 from Tom Brennan Software. There are numerous others from software vendors like Rocket Software.

Some IT teams have got their IT staff to connect from their home computer to their office computer. Once they’ve logged in to their work computer, they can connect to the mainframe in the usual way using the terminal emulator installed on that computer. Connecting from their home computer to the office can be done using something like Microsoft Remote Desktop Protocol (RDP). Other organizations have used a Virtual Private Network (VPN) to allow employees to securely connect from home to their corporate network, and then access the mainframe.

These were all great ways to get connected as the pandemic and lockdown required that people be able to work from home, but now that we are, hopefully, coming out of the worst of things, it makes sense to re-evaluate our way of working and see whether there might be a better way of connecting mainframe-using employees to the mainframe.

Now is the time to ask the question, “what do users want?” as well as simply, “how can we do it?” And what users seem to want at the moment is to work from any device with a browser. It’s what they tend to do for everything they spend time on – shopping, social media, etc. So, how can we give mainframe-users a browser interface.

Virtel has been doing this for some time with Virtel Web Access (VWA). What it does is securely serve 3270 screens as standard HTML webpages over encrypted HTTPS connections to browsers. Using a browser, users see the interface that they are familiar with. The 3270 terminal emulation is a web browser.

Similarly, Rocket Software has Rocket Terminal Emulator (Web Edition), which used to be called Rocket® BlueZone Web. This, they say, delivers secure, browser-based emulation to any device, including desktops, laptops, tablets, or other mobile devices. This allows users to access mainframe applications from any browser, anywhere.

Macro 4 has Tubes, its session management software that comes with a web interface. This can web-enable mainframe applications from the user’s point of view, and employees can then access mainframes from any device with a web browser. Tubes provide a single point of entry for a user to all the applications that they’re allowed to access. And users can change from one application to another without having to log off and on again. A web-enabled session manger allows users to work on 3270 applications on any sized screen and use mouse clicks and even touch-screen commands to get work done. 3270 session manager software is available from other vendors.

A more complex solution for CICS users is provided by HostBridge Technology. They have the HostBridge JavaScript Engine (HB.js), which enables the creation of JavaScript/JSON-based integration scripts and APIs. HB.js scripts work with all types of CICS applications without relying on screen scraping. HB.js is a complete solution for rapidly developing and deploying reusable Web services and/or scripts. That takes things a whole step further in integrating mainframe CICS applications with the outside world in general, not just staff working from home using a browser.

Some people may want to connect to the mainframe to develop code. One way to do that is to use Visual Studio Code, a source-code editor from Microsoft that runs on Windows or Linux. Users can then interact with z/OS in the Terminal window by using commands provided by IBM RSE API plug-in for Zowe CLI (RSE CLI plug-in), Zowe CLI, or both. The Zowe Explorer extension for VSCode lets users interact with data sets, USS files, and jobs that are stored on z/OS. The extension can be installed directly to VSCode to enable the extension within the GUI.

The real gold standard, the piece of software that seems to be missing from these choices that are available is web browser gateway software actually running on z/OS. It would allow z/OS applications to interoperate with other platforms (like Windows, Linux, and the cloud) in real time and users could interact with their mainframe in the same way that they do other platforms. There would be standard interfaces such as XML, HTTPS, and REST APIs. Interfaces that plenty of people are familiar with and could use easily, and there would be no need for specialists from other platforms.

And because this gateway software would actually run on the mainframe, there would be no need to access mainframe applications through a Linux of Windows server first. There would also be no need for any new hardware, or support, or repackaging. As far as the mainframe team would be concerned, they would simply install a piece of software on their mainframe – it could either run inside a z/OS based server address space or in a standalone address space – and everyone who was authorized could directly access any application functions they were authorized to access.

I guess everyone has their own favourite way of connecting remotely to a mainframe. ‘Green screens’ allow mainframe experts to work quickly and efficiently, and so terminal emulation is very common – and has been for a long time. I guess the important thing is to be able to get the work done remotely. However, there must be a better, more modern way of doing things, don’t you think?