Mainframe in the App Store–2022

Feature Photo Courtesy of Pexels

“There seems to be no mainframe explanation for the PC world in which we’re living.”

— William J. Clinton, President of the United States, in 1995.

In current technology, the PC still frequently interfaces with the Mainframe. One example of this connection is to use a PC to access backend Mainframe programs that process large amounts of data more efficiently. We are thought to have entered the 14th year in the era of the iPhone, and I have not personally used a connection between the Apple (iPhone/iPad) and the Mainframe. I wondered if there was one, so I did a quick search on ‘IBM Mainframe’ in the App Store. I got these 6 results:

  1. IBM HMC Mobile
  2. TN3270 Lite
  3. Julianator
  4. Reflection TN3270 TN5250 Lite
  5. z/Reference
  6. Reflection for TN3270 & TN5250

It seems that there is a place for the Mainframe in the App world after all–the old-fashioned meets the brand-new.

The info below is a brief discussion of each App on the above list. It’s not meant to be a review or a rating, just some cursory observations. Perhaps later blog postings will follow with more detail.

IBM HMC Mobile

The first App’ is subtitled ‘for Z and LinuxONE’ . This App was developed by IBM and refers to the Hardware Management Console (HMC), which allows you to configure and manage servers. According to the description, the App lets you to manage your systems from your mobile device. There are a wide variety of Key Features listed for system usage. A new version with more security features was introduced only 2 months ago, an indication that the App has been updated recently. In fact, there are two Copyrights for this App—2013 and 2022.

TN3270 Lite

This App is subtitled ‘Gives easy access to a server’.  The description is that it emulates an IBM 3278 terminal for easy access to an IBM Mainframe. However, being a Lite version, it only provides a 5-minute session. There are several Features listed, and it claims to support all standard 3270 emulation features. One interesting mention is that it allows the camera to be used as a barcode scanner, which doesn’t seem extremely secure. It should be noted that this is not an Attachmate product (as the other Emulators on the list are).


This App’s function is to convert a date between a Julian Day of the Year and a Gregorian Day of the Year. It is meant to work with Julian dates that are found in a Mainframe Legacy system. There are no recent updates, but it did get a 3 out of 5 rating. The Copyright is 2015.

Screenshot from the App Store

Reflection TN3270 TN5250 Lite

This Lite version, by Attachmate, basically allows users to evaluate the Reflection for TN3270 & TN5250 Emulator App for free before buying it. The description states that the full Emulator lets you ‘administer your mainframe from the coffee shop while enjoying your morning mocha’. The Lite product makes available testing to ensure that the full-blown Emulator is a good fit. There are positive reviews in the description, as well as a list of Recent Enhancements. The Copyright is 2020


This App is a technical reference for IBM’s z/Architecture Reference Summary. Some of the sections in the menu are the following: Assembler, Condition Codes, Instructions, and Interrupts. There is also an extensive list of Features in the description. The Copyright is 2022.

This is one App I would be excited to get and try out. I see this as a future research subject, as well as an App to be used in a practical way. I will definitely be adding this App to my list of future post topics.

Screenshot of z/Reference Assembler Instructions

Reflection for TN3270 & TN5250

This is the full-blown version of the ‘Lite’ Attachmate version described above. It connects iPad/iPhone devices to Mainframe and AS/400 systems. It is described as the enterprise-class terminal emulation client for ‘3270 and 5250 terminal emulation on the go’. Again, there are positive reviews as well as a list of Recent Enhancements. The Copyright, like the Lite version, is 2020.

Screenshot from the App Store of Emulator Enhancements and Connections


As predicted, there wasn’t too much to be found when searching on ‘IBM Mainframe’ in the App Store. Loved the fact that there were a couple of very promising Apps in terms of the Mainframe Emulator and one that promised that ‘Reflection for TN3270 and TN5250 will delight’.

Let me know if you would like to see more content on Mainframe-related Apps. It seems that even the Mainframe realm has found its way into the domain of the App Store.



COBOL–Working With It

Image from Canva, Edited in Canva to add text

The Common Business Oriented Language (COBOL) computer programming language is over 60 years old. Some consider it to be outdated, and those that program in it have been jokingly called dinosaurs. However, COBOL is still widely in use in banks, insurance companies, governments, and other financial institutions to efficiently and securely process large amounts of data through computer programs run on Mainframes. There are basically 2 different forms of COBOL program processing: Batch and Online.

Batch Processing

Batch COBOL programs are scheduled through Job Control Language (JCL) jobs to be run at a specific time, in a certain order. For example, data may be batched in files and processed overnight to update a DB2 database. JCL jobs are set to specify who has access to run the program as well as time parameters. The input data file names are also included in the JCL job, along with the COBOL program name and an output location.

Online Processing

There are CICS (Customer Information Control System) programs that are online COBOL programs containing CICS commands. They are run in real-time for screen display and data capture. For instance, while programs run in the background, screens are displayed to a user to allow data entry. The data captured is processed and saved, possibly to a DB2 database.

Coding Environment

The COBOL coding environment is typically an interactive TSO (Time Sharing Option) session on a Mainframe computer. If you would like more details, IBM has a What is TSO section on their website. Most users work with TSO through its menu-driven interface, Interactive System Productivity Facility (ISPF). What is ISPF is also available through the IBM website.

In summary, COBOL programs are compiled and run in a Mainframe TSO environment, using an ISPF interface. These programs can be set to run on a schedule in a JCL job, using batch processing; or through an online environment, using CICS.

What other COBOL-related items would you like to see explained in more detail?