Prepare To Evacuate
It is rare to need to evacuate hardware. But being rare is not an excuse to neglect to plan for it. Obviously I’ve been sensitised to the question by real customer situations - though I don’t intend to describe the situations in any detail; This post should prove useful enough without doing that. When I say “rare” hardware generation upgrades usually require giving the machine over.
http://mainframeperformancetopics.com/2026/02/22/prepare-to-evacuate/
What’s Important? CICS Transaction vs Region Goals
When assessing how well a WLM policy protects key work it’s necessary to understand how much CPU is used at each importance level. \ If there is very little work at a lower importance (higher importance number) a CPU crunch will leave work at this importance level vulnerable to CPU queuing. Let me give a real, recent example: Db2 “Engine” (DBM1, MSTR, DIST address spaces) were in a service class at Importance 1 - with CPU Critical enabled.
http://mainframeperformancetopics.com/2026/02/22/whats-important-cics-transaction-vs-region-goals/
md2pptx v6.2 released with a couple of nice enhancements:
1. Figure Captions
2. Allowing multiple bulleted / numbered list blocks on a slide.
Two Of These Are Not Like The Others
They were simpler times back then. “Back when?” You might ask. When PR/SM got started - in the mid 1980’s - a machine might have two or three LPARs. Similarly, when Parallel Sysplex got started the number of members was very small. For reference, a z17 ME1 can have up to 85 LPARs, and a Parallel Sysplex up to 32 members.
http://mainframeperformancetopics.com/2025/12/15/two-of-these-are-not-like-the-others/
Modern Machines, Modern Metrics
Modern Machines, Modern Metrics In z17 Sustainability Metrics - Part 0 I wrote about the new z17 Sustainability Metrics, or “Power Consumption”, if you prefer. This post isn’t part 1 - as I don’t intend to go into much detail about what I’ve learnt so far. I have learnt things, of course. During the Summer it occurred to me that there are a number of things that are new in z/OS instrumentation on z16 and z17.
http://mainframeperformancetopics.com/2025/12/06/modern-machines-modern-metrics/
md2pptx 6 Is Another Big Step Forward
If the purpose of Version 5 was to add the ability to use Python in the context of md2pptx the purpose of version 6 is to extend md2pptx’s automation capabilities still further. This time instead of Python it’s AppleScript. The context is different too: With Version 5 the Python support runs the user-supplied code as part of the main md2pptx run - before the PowerPoint presentation is saved.
http://mainframeperformancetopics.com/2025/12/06/md2pptx-6-is-another-big-step-forward/
md2pptx 5 Is A Big Step Forward
A while back I experimented with executing user-provided Python. It seemed a small step at the time, but I had a hunch it would turn out to be a much bigger thing. Coding it was straightforward but two things delayed releasing it: Documentation is tricky. The python-pptx API is (necessarily) not for the faint of heart. But why bother in the first place?
http://mainframeperformancetopics.com/2025/12/06/md2pptx-5-is-a-big-step-forward/
mdpre Comes Of Age
I wondered a while back why I hadn’t got mdpre to 1.0. It turns out there were still some things I felt it needed to have it “graduate”. I suppose I should explain what mdpre actually is. It’s a tool for preprocessing text into Markdown, This text is “almost Markdown” or “Markdown+” so you can think of it as a tool people who normally write in Markdown could value.
http://mainframeperformancetopics.com/2025/12/05/mdpre-comes-of-age/
REXX And Python
A long time ago I wrote blog posts about driving Unix System Services from REXX. My motivation at the time was relatively minor. Now, however, I have a stronger motivation: Python. You might or might not be aware that z/OS has modern Python support - and I expect it to keep up very well as Python evolves. For reference, here are the three blog posts from long ago.
http://mainframeperformancetopics.com/2025/12/05/rexx-and-python/
Well, That’s Embarrassing
I’ve had a task on my to-do list for some time now to assess the state of my blog and publish some posts I knew I had drafted. Typically I write posts while in the air - as there’s precious little else to do. So I’d written several - some with more topicality than others. I think a general state of being extremely busy with customer engagements and conferences has led to me not getting round to posting them.
http://mainframeperformancetopics.com/2025/12/05/well-thats-embarrassing/
