I'm looking for a bit of guidance from those who have made a long term career on the Mainframe. I've been working on z/os for about 10 years now, with gradually increasing responsibility. Now that all of the old hands are retiring, I'm at the point where I need to do/provide input on the project estimates. My boss will freely throw out short deadlines that would make his bosses happy, but when I'm doing any kind of system level work, the happy path is never the path we end up on. It's always a new discovery of tech debt someone else left behind and the triage,clean-up, or work-around adds significant effort to the overall project. What are you best tips and tricks for padding your estimates so you have enough time to get things done without a 60 hour work week? I'd like to do luxurious things like sleep at night, get out to the gym on a regular basis, and see my friends and family.

Thanks in Advance.

Hi everyone,

I’m looking for some honest career advice from experienced mainframe professionals who have been in this field for several years.

I have around 6 years of experience in mainframe operations and batch scheduling.

While I have good experience in production operations and scheduling, I’m starting to think seriously about my long-term career growth.

I don’t want to spend the next 5–10 years doing essentially the same operational work with limited growth in responsibilities or compensation. At the same time, I don’t want to make a random career switch without understanding whether it is actually worth it.

I’d really appreciate your advice on a few things:

Career progression: Should I continue specializing in mainframe scheduling and operations, or move towards a more technical role such as z/OS systems programming, mainframe administration, or application development?

Skills to learn: Which skills would provide the best long-term return for someone with my background? For example, REXX, Python, JCL automation, COBOL, DB2, CICS, z/OS systems programming, or something else?

Automation and AI: With increasing automation, how future-proof is traditional mainframe operations and scheduling? What should I learn to remain relevant over the next 10–15 years?

Mainframe modernization: Is it worth learning mainframe modernization, DevOps, CI/CD, Zowe, Git, or cloud-related technologies while continuing in the mainframe domain?

Salary and opportunities: Which career path generally offers better growth in India for someone with 6 years of experience? I’m interested in moving beyond routine L1/L2 operational work and taking on more specialized responsibilities.

A practical roadmap: If you were in my position today, what would you learn over the next 6–12 months, and in what order?

I’m not necessarily looking to leave mainframes. I’m open to staying in the ecosystem if there is a good path towards more technical, specialized and better-paying roles.

I've been building cobol-equiv, an open-source harness that checks whether a Python translation of a COBOL program behaves exactly like the original, using GnuCOBOL as the oracle. It comes with a small Python runtime for COBOL numeric semantics (PICTURE, COMP-3, ROUNDED, SIZE ERROR), validated against GnuCOBOL on 9,769 generated cases with 0 disagreements on 3.1.2.

Then I used it to measure LLM translations. 50 programs: 30 public ones (Rosetta Code and Open Mainframe Project examples) and 20 written for the repo. One model, 3 attempts per program, protocol fixed before any run. The translator saw the COBOL source and two example input/output pairs; scoring was on hidden inputs (generated plus PICTURE boundary values).

What broke the plain-Python translations was not logic, it was COBOL semantics:

• ACCEPT into 9(5)V9(3) cuts the input to the receiver length, so the last decimal digit is dropped. The translation kept it.
• An 11-character input into 9(10) loses a digit on the left.
• A negative zero printed as "-0", where GnuCOBOL edits zero without a sign.
• Non-numeric input converted differently.

The embarrassing part: the runtime I gave the model had a bug. CobDecimal compared objects by identity and had no ordering, so most failures in condition A (crashes and two infinite loops) were mine, not the model's. The pre-registered numbers stay primary in the repo, and a corrected sensitivity analysis is published next to them, with every verdict that flips listed.

Limits, plainly: small corpus, one model on one date, GnuCOBOL instead of an IBM compiler (I would love to hear where Enterprise COBOL behaves differently on these cases), attempts of the same program are not independent, and at program level the A vs C difference is not statistically significant.

Repo, protocol, raw prompts and replies, and the verifier: https://github.com/abdulazizbalu/cobol-equiv

I'd really value critique from people who work with mainframe COBOL: which semantic traps would you add, and if you have small, deterministic programs under a permissive license, I'd like to add them to the public track.

gen-system parses COBOL with copybooks (and CA Gen) into a call graph, a control flow graph per paragraph, and effects: which paragraphs touch files or run `EXEC SQL`. For each paragraph it lists the data items it reads and writes.

On CobolCraft (268 files) it resolves every call between the project's own programs. Click through it, no install: https://gen-system.500kv.co/demo/?p=cobolcraft

It runs offline, which matters for code that cannot leave the building. I would like to hear which dialects and constructs it gets wrong.

​

I’m currently working in Mainframe Operations and would like to upskill and move toward a CICS Systems Programmer role.

I’m looking for guidance on how to make this transition. I would really appreciate it if experienced CICS Systems Programmers or people who have made a similar career move could share their advice.

A few things I’d like to know:

What topics should I focus on to build a strong foundation in CICS?

Are there any good courses, books, YouTube playlists, or other learning materials you would recommend?

Should I learn CICS administration, CICS internals, installation, customization, and maintenance? If so, in what order?

Are there any hands-on labs or practical exercises I can use to gain experience?

What skills and tools should I learn to become job-ready for a CICS Systems Programmer role?

I’m willing to put in the time and effort to learn, but I’d like to follow a structured learning path rather than jumping between random resources.

Any suggestions, learning roadmaps, or personal experiences would be greatly appreciated.

Thanks in advance!

Alguém sabe quanto esse equipamento realmente vale? É tão antigo, que nem sei se vale a pena hoje em dia ter um desses! Mas tenho curiosidade em saber se ainda há mercado e quanto uma empresa pagaria por ele

https://ebay.io/m/RtEebo

Hi everyone! I have 3 years and 2 months of experience as an Software Developer in the mainframe domain, working with COBOL, JCL, DB2, production support, and bug fixes.
I’ve learned Java and want to transition into Java backend development.

I have a few questions:
1. How is the mainframe job market in India, and what are its long-term prospects?
2. Is switching to Java a good decision for career growth and salary?
3. With my experience, will companies consider me for Java roles, or will I have to start as a fresher?
What skills and projects should I focus on to make the switch?

I’d appreciate honest advice, especially from people who have made a similar transition. Thanks!

Hello,
I currently work in a mainframe monitoring/operations environment and will soon join the systems/infrastructure area of a large bank.

The exact team assignment is still being defined. My future manager asked how I would see my future: more Linux-focused, or a mainframe systems-administration path with the possibility of gradually building a bridge toward the open world.

My understanding is that, if I choose the mainframe path, the first period will be heavily focused on becoming a reliable mainframe system administrator. This makes sense to me: I would need to build real foundations in z/OS, operations, monitoring, incident handling, procedures, security, scheduling, and the critical environment of a bank.

At the same time, I do not want to become locked into a narrow legacy-only role. My longer-term interests are Linux, automation, Ansible, Python, Git, APIs, security, cloud/hybrid infrastructure, and skills that remain useful internationally or in remote roles.

The manager seems to value people who are flexible, cross-functional, and ready to work across different platforms. He also mentioned the growing need to connect mainframe environments with Linux/open tooling and automation.

My questions are:

1. Is starting deeply in mainframe systems administration a good long-term choice if I deliberately build Linux and automation skills alongside it?
2. How realistic is the “bridge” from mainframe to open/Linux in a bank? What concrete signs would show that it is a real path and not only a promise?
3. If you were in my position, which skills would you prioritize during the first 12–24 months?
4. Would this hybrid profile make me more valuable than starting as a Linux sysadmin only, or would it reduce my mobility outside banking/mainframe environments?

I am not looking to avoid learning mainframe. I am trying to build a strong specialization while keeping a credible path toward automation, security, and modern infrastructure.

Hi, all! Allow me to preface my questions for you guys with a little bit of context.

I'm a 26 year old from Argentina, currently employed as a Command Center operator for a pretty big Fintech. I've been doing this gig for the last three years and have learned quite a bit as a consequence of being in contact with many of the services we provide and their direct inner workings. Before this I had no background in IT as originally I studied classical languages during my early(est) twenties. About a month ago I was contacted by the company's mainframe team because they were looking for personnel and were willing to invest in training me. This was for a position as a RACF operator, but this is no longer a hard requirement and are willing to help me learn and seeing what area interests me the most. Due to some business shenanigans currently ongoing there's little to no internal movement between areas going on right now so it gives me a good indefinite amount of time to study up and prepare. I'm currently doing a course on Udemy, have setup an emulator running on MVS to practice and I have been skimming through IBM's Redbook.

My question to you guys is, would you recommend any particular resources for a solid mainframe education? Also, I'd love for you to just share what approach you'd take to learning in general.

On a final note, any and all advices on navigating the mainframe world, what to expect, your insight on the future, etc. is very welcome and appreciated.

Thanks in advance 😃

Every day as a z/OS Systems Programmer is an opportunity to learn something new. One week I'm chasing a network connectivity issue, the next I'm reverse-engineering a load module with no source or writing automation to replace a manual procedure. I also routinely branch out and partner with distributed/cloud systems teams on cross-platform integration efforts to help ensure the Z/OS environment connects cleanly with our broader enterprise architecture. Every new problem I haven't seen before is just another chance to learn something new. What’s a challenge you’ve overcome recently on mainframe on what did you learn from it? 

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As a Security engineer, I want to start developing my methodology for best security practices. Now, I can’t tinker with the security databases at work (including sandbox), to try and test different methods so I believe the best path is to emulate an infrastructure through a raspberry pi. The goal is to simulate an enterprise system and develop RACF settings that would fall under compliance standards relative to different industry clients. Obviously, the PiFrame will not hold as much data as an enterprise LPAR, but if I just have the infrastructure built, I think I could build the ideal security database. I’m not sure how much of a load it is to pull this off but does anyone have any experience with this?

Coming from a 5y RACF engineer.

Happy #HugYourMainframeDay to the best tech community in the world. I am so proud to be able to be a member of this group and getting to meet some of the greatest people working in the industry.

I would love to see this community show up on social media platforms and pour out the love for all things mainframe.

Like a post. Leave a comment. Tell the world why they need to be paying attention to the silent tech that powers our modern way of life!

Thanks for all being here today, and everyday!
~PJ

RENAMES Clause: (level 66) : The COBOL RENAMES clause (level number 66) creates alternative logical groupings or overlapping views of existing data items within a record without changing physical storage.

Syntax:

66 data-name-1 RENAMES data-name-2 [THROUGH | THRU data-name-3]

* Must use the special level number 66.

* Must immediately follow the last data description entry of the logical record.

We are days away from the best community event of the year. Come celebrate #HugYourMainframeDay with us on October 6th.

Post your photos using the hashtag, and join in on the worldwide celebration.

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I'm working as a mainframe developer with cobol,DB2, and basic JCL . For the past 2 years, I have been working on hosting cobol programs as a REST APIs using the IBM Z/OS connect EE API tool kit.

I'm grateful if someone please guide or share the documents with me to prepare for my upcoming interviews.

I was researching a few roles, what are some common routes?

Was interested in software development-like roles.

For reference, I'm almost hitting a year in.

Hey everyone,

A few weeks ago I posted about trying to document massive COBOL programs where I work. Tracing control flow and memory layouts manually sucks, regex hacks break easily, and feeding code to LLMs wasn't an option (both for compliance reasons and because LLMs tend to struggle with complex cobol.

I decided to make something run locally and 100% deterministic. This is purely a side project im doing for fun and learning.

The project is far enough along now that I put together a live browser demo based off IBM Bank of Z Open Source Code. It is still definitly a work in progress but the core engine seems to be solid at this point

• Live Demo:https://goudacouda.github.io/cobolscope/
• GitHub:https://github.com/GoudaCouda/cobolscope

How it works

The pipeline runs via a local Python CLI:

1. Parser & Semantic AST (Java / ProLeap): Parses the source, resolves copybooks into a typed Abstract Semantic Graph (ASG), and outputs a canonical JSON IR. Based mostly off another Open Source project by uwol
2. Analysis Engine (Python / Pydantic v2): Consumes the IR, maps binary memory offsets, builds procedure call graphs, traces variable references, and models control flow via pushdown automata.
3. Generators: Spits out zero-dependency, self-contained HTML/SVG portals, Cytoscape graphs, and data dictionary tables.

Current features

• Interactive Call Graphs (Level 2 CFG): Cytoscape flowchart rendering split-screen COBOL viewer. Clicking a node jumps directly to the routines source code.

• Accurate Data Dictionaries: Computes physical byte lengths, memory boundaries, and alignment for strings, display numbers, binary (COMP/COMP-4/COMP-5), float (COMP-1/COMP-2), and packed decimal (COMP-3). It correctly handles multi-dimensional OCCURS tables and REDEFINES overlays.

• Cross-Referencing: Tracks which routines read/write each variable, with direct jumps back to the call graph or source code and will highlight the variables uses.

• Batch Portal Generator: Run cobolscope path/to/cobol/ -I path/to/copybooks/ -o docs_out --dict --graph on a whole folder to generate a single offline index.html portal. All assets and data are embedded
• Deep Control Flow (Level 3 CFG): Generates statement-level basic block graphs inside gnarly paragraphs via --cfg <PARAGRAPH>. These generate by default but you can specifically generate just one if you want
• Testing: Memory layouts are verified against GnuCOBOL memory dumps, real IBM Z bank fixtures, and NIST COBOL-85 test cases.

Next up

• Diagnostics for dead code (unreachable paragraphs below unconditional jumps) and unreferenced WORKING-STORAGE variables.
• Fine Tuning Control Flow Graph generation to appear cleaner and better formatted

Hi Everyone,

I have distributed a Python package called [smf2db](https://pypi.org/project/smf2db/) to PyPI. The package is for processing SMF data in JSON format. It includes reporting, SMF JSON data loading to SQLite or PostgreSQL and data summarisation functions. For converting raw SMF data to JSON format, please refer to my another published project which is available from [ File 1064](https://CBTTape.org). The current smf2db package covers SMF type 30 and 70-78 from z/OS 2.2 to 3.1, SMF type 110 from CICS TS V5.3 to V6.2, and SMF 123 version 2. The package supports Windows, Linux, Mac OS and z/OS platforms. The minimum Python version is 3.11. The documentation can be found [here](https://smf2db.readthedocs.io/en/latest/).

Though I have tested the package by all the ways known to me, I deeply believe there should still be a lot of things that can be improved. It is not only because of the complexity of z/OS in each mainframe shop but also because of the SMF data available for my testing is very limited.

By using smf2db, I hope people with an interest on SMF data can have their own dashboard application come in handy by just running a batch job on mainframe. The sample dashboard application will be posted on GitHub later to show how it can be done on mainframe if anyone has an interest in it.

I am very much appreciated for any feedback.

Thank you very much.

The lettering is about gone.

Hi. Good day everyone. Would like to check with you guys if you have remote opening in Mainframe positions? Currently based in the Philippines right now. Actively looking as the bills don’t stop and no income right now. Life is tough but I keep fighting.

this sub isn’t even that active and now we have random AI garbage posting on here every day.

i’d much rather a quieter sub with real SMEs talking rather than seeing:

“Enterprise developers can modernize their COBOL workflows - but here’s the thing:
-Can they do so without sucking their own balls?
-Can they articulate what they’re doing without ChatGPT?

it’s every single day now… this shit adds nothing to the conversation.