About Network Testing Labs

Contact Network Testing Labs

Independent Reviews of Network Hardware and Software



CA's Mainframe Chorus


A 21st century mainframe user interface to replace 3270 “green screens”
By Barry Nance

Executive Summary
CA Technologies has designed a new mainframe user interface which, according to the company, will make both novices and pros more productive. Called Chorus, it replaces 3270 "green screen" terminal access with a graphical, browser-based interface accessible from any current desktop computer.

Despite years of increased use of desktops and laptops, mainframes remain essential to enterprise computing. Companies like Conagra, JC Penney, Travelers Insurance, Ford Motor Company and Wal-Mart use mainframes to run core business applications as well as provide data storage and data access for critical corporate assets. Unfortunately, mainframe user access all too often still relies on 3270 terminals (typically via terminal emulation). The 3270 “green-screen” terminal user interface is a clunky, arcane, single-window view into the mainframe that’s changed little in decades.

Historically, attempts to replace the 3270 interface have been less than successful. The first such approach was screen scraping, in which a PC stored a 3270 screen in memory, picked up data from that memory image and displayed the data in a manner different from how a 3270 terminal would display it. For instance, a screen-scraping program might re-interpret codes and abbreviations on a screen to present the data in a less cryptic form, or might pick up specific data from the screen contents and forward the selected data to another application.

In 2002, IBM WebSphere Host Access Transformation Services (since rebranded Rational Host Access Transformation Services), a sophisticated 3270-to-HTML translator, was introduced. Unfortunately, a 3270 screen rendered as a Web page is still just a 3270 screen. Some mainframe application vendors such as SAP have offered rather snazzy Windows-based interfaces to replace 3270 access to the application, but these are proprietary.

A paradigm shift
Chorus is definitely a paradigm shift for mainframe user interfaces. A mix of mainframe Java and C code, Chorus provides what CA terms “role-based workspaces.” In these workspaces, Chorus can vary its content (e.g., verbose or terse) to suit the user’s experience level, adjust the organization and presentation of data to suit the task at hand and provide context-sensitive access to both help files and collaborative data.

It can also personalize the display of content, the organization of the content and the level of available assistance to help a user accomplish tasks more easily. Chorus is aware of task dependencies and will, for instance, automatically open additional workspaces to ensure the user completes all the steps associated with a task.

Chorus runs on the mainframe, alongside the application it supports (you can visualize Chorus as an overlay on top of the target application). It interacts directly with the mainframe application to both control the application and obtain status information. It then presents the data in a flexible browser-based interface using JavaScript and, occasionally, Java applets. The result is a dynamic point-and-click visual environment.

The first incarnation of Chorus, released late this past November, works with DB2 for z/OS to give database administrators a graphical workspace in which to manage their databases. CA is working on Chorus-based interfaces for other mainframe applications in the areas of security, storage and workload. CA also says it plans to make the Chorus architecture, including Java libraries and design techniques, generally available to developers.

I put Chorus through its paces remotely, from my network lab, to judge how productive and effective Chorus is. I used it to accomplish four tasks: Research DB2 for z/OS performance by producing time series graphs, visualize DB2 database objects, get online help, and migrate DB2 objects. For comparison purposes, I also used 3270 terminal emulation to do the same tasks.

For each task, I evaluated the extent to which Chorus would help a both a novice and a pro do the work.

DB2 Performance Factors
Investigating DB2 performance classically entails creating DB2 data definition statements, creating DB2 Structured Query Language statements, running a series of batch jobs, transferring results to a PC and then graphing them with Excel. The process is tedious and highly iterative, because you often have to refine your research as you analyze results. The effort usually takes several hours to work through.

When I tried the same task with Chorus, analyzing DB2 performance required just a few mouse clicks. Novices doing this job with Chorus would be glad for the contextual, graphical environment that would keep them from getting lost along the way. A pro would appreciate being able to quickly investigate a variety of DB2 performance considerations without waiting long minutes or hours to obtain new performance results.

Visualizing Database Objects
With the classic approach, searching for DB2 objects and visualizing the relationships among those objects is an exercise that can tax even the most creative mind. In contrast, the Chorus browser window for performing object dependency searches makes the task much simpler. In short order, I not only listed the dependencies but could see them graphically depicted on the screen. A novice would be at ease in this intuitive, graphical environment, while a pro would save considerable time obtaining and understanding the DB2 object data, its relationships and its interdependencies.

Online Help
Windows users can get context-sensitive help by simply pressing the F1 key. 3270 terminal users don’t have this luxury. Often, 3270 users create text files of helpful hints and open multiple terminal emulator windows so they can see the text files at the same time they’re trying to accomplish some arcane task.

Chorus offers access to a screen of helpful “knowledge center” information. With Chorus, pressing the question mark key displays context-sensitive help, and Chorus’ help facility has a search engine that works much like Windows’ "search help" function. Chorus’ help facility is clearly a big plus for novice users, and pros will save time and avoid the distraction of having to search for something in the middle of some task.

Migrate DB2 Objects
The need to migrate DB2 objects from one set of databases to another occurs frequently in many companies. The classic method of performing the migrations involves submitting batch mainframe jobs. The process can be frustrating for a novice who isn’t well-versed in JCL or in DB2 control statements.

With Chorus, the novice can focus on the migration instead of the JCL because Chorus performs the actions in real time. Novices will also be delighted to find that Chorus offers a wizard for migrating DB2 objects. Pros will like how Chorus saves them time, especially when hundreds of objects have to be migrated every few days.

Issues with Chorus
Chorus isn't perfect.

First, Chorus is written mostly in Java, which is an interpreted language. Unlike other, compiled languages, Java mainframe software (consisting of the Java Virtual Machine or JVM) looks at each Java programming statement, interprets it and then executes machine instructions to accomplish what the Java statement specified. This interpreted language environment can consume considerable CPU resources.

IBM’s (and thus CA’s) answer is a specialty engine, hardware that you purchase as a mainframe add-on and that can execute Java language programs fairly quickly. A specialty engine isn’t terribly expensive, as mainframe hardware goes -- about $125,000 each. And the increase in user productivity can be worth it. But be aware that Chorus can run a little slowly on a busy mainframe that lacks a specialty engine add-on.

For any application, users invariably clamor for user interface enhancements. Because Chorus dynamically handles every detail of the user interface, it’s particularly susceptible to such user requests. According to CA, the company already has a backlog of user interface enhancement requests from beta testers and early adopters. A company that embraces the Chorus architecture may find it needs to devote significant time to user interface design and workflow analysis.

Chorus’ success will hinge on CA making the Chorus architecture generally available to mainframe programmers and designers who want to improve their applications’ user interfaces. How well CA handles the licensing and distribution of the Chorus architecture and libraries will determine its fate.

While many vendors have over the years created graphical interfaces for various mainframe applications, Chorus’ new architectural approach promises to give users a feature-rich graphical environment that dynamically tailors itself to suit both the task at hand and the user’s experience level. In fact, I found the graphical interface, impressive though it is, to be the least important part of Chorus.

Chorus’ strength is that it understands what the user is accomplishing and guides the user along the way. It turns a “Oh, heck, what do I do now?” situation into a “Oh, of course, that’s what I want to do” and a “Oh, yes, I don’t want to forget to do that step” situation.

Copyright 2012 Network Testing Labs


About Network Testing Labs

Contact Network Testing Labs