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LongEx Mainframe Quarterly - May 2023

opinion: Ten Reasons Why I'm a z/OS Geek

I'm a real z/OS geek. Love working with z/OS, love finding more about it. To convince you, let me tell you my top ten reasons why I think I'm a total, complete, hopeless z/OS geek.

  1. I regularly check out the z/OS base elements for new things: kind of like window shopping for z/OS geeks. Did you know that z/OS 2.5 adds the IBM Z Deep Neural Network (zDNN) Library? APIs to use the new AI features of the z16 processor.

    It's also nice to look at some of those old features that aren't used much today. Who still uses Bulk Data Transfer (BDT)? OK, one of my clients.

  2. I get excited when I work with Assembler Code: I may even giggle a little bit. Like those people watching football, I like to find faults or criticise code I'm looking at it: "look at that, they're still using STM to save the registers: BAKR is much better".

  3. I start talking faster whenever I talk about mainframes to someone (anyone): particularly if I think I know more about mainframes than they do. I often stand alone at mainframe social events.

  4. I still have copies (yes, more than one) of the z/Architecture Reference Summary booklets. Here's my collection:


    From the left, summaries that can be used with MVS/XA, MVS/ESA, and z/OS.

    You'll have noticed that my name is on every one: these were hard to get, and easy to steal. Today, we don't need to horde these booklets: it's all provided free by IBM in PDF format.

  5. When I heard that Adam Savage (from the TV show Mythbusters) had some mainframe stuff, I instantly found the YouTube video. When he shows a 3380 head disk assembly (HDA), I got a little excited, remembering when I helped an IBM engineer replace one.

    During this video, Adam mentions the book "The Soul of a New Machine". I went and read it: and was disappointed when it talked about developing a Data General computer, not an IBM mainframe.

  6. I get a little starstruck when I meet, or even see, z/OS stars like Cheryl Watson, Barry Merrill or Peter Enrico. I remember attending my first Share conference in the US and being a little overwhelmed at the thought of hearing sessions from the "mainframe famous."

  7. When I was younger, I read "Merrill's Expanded Guide to Performance Evaluation Using SAS Systems" from cover to cover: all 800+ pages. In its day, this book was the bible for performance measurement, but it is not an easy read (sorry Barry). To make things worse, I know if a site has Merrill MXG installed, I can reread this book in the SOURCLIB dataset (look for the ACHAP* members).

  8. Some people will daydream about a past holiday or great party they went to. I sometimes daydream about technical things that I've done in the past that I thought were cool. "That's right, I wrote an SRB routine to hop over to another address space to access those control blocks – gee I was smart". Must remember to keep these daydreams to myself.

  9. When I first started with z/OS, I hand wrote notes as I learned things. I still have those notes, and occasionally refer to them:

    If you look closely, you'll see that the paper looks like old computer paper. That's because it is: blank pages from our mainframe's 3800 laser printer.

  10. I write geeky mainframe articles like this one.

I'm not convinced that being a z/OS geek is that trendy: I'm sure hackers and other geeks will be more popular at parties. But being a z/OS geek is what I am, and it's not so bad.


David Stephens