Category Archives: Uncategorized

(Originally posted 2016-02-14.) I wish I’d started counting DB2 subsystems before. A recent study saw 43 DB2 subsystems, in 13 Data Sharing groups (and a few in none), across a large number of z/OS systems. And if I try to remember other studies these numbers have been typical of them (but this is not aContinue reading “Suffering Subsystems”

(Originally posted 2016-01-24.) DDF and Batch sound like two opposite ends of the spectrum, don’t they? Well, it turns out they’re not. I said in DDF Counts I might well have more to say about DDF. I was right. I’ve known for a long time that some DDF work can come in from other z/OSContinue reading “DDF Batch”

(Originally posted 2016-01-17.) I don’t think I’ve ever written very much about DDF. Now seems like a good time to start. I say this because I’ve been working pretty intensively over the last couple of weeks on upgrading our DDF Analysis code. Hence the recent DFSORT post (DFSORT Tables). I’m actually not the DB2 specialistContinue reading “DDF Counts”

(Originally posted 2016-01-10.) It’s been a while since I posted a DFSORT trick – and it’s high time I did. This post follows (distantly) on from More Maintainable DFSORT and is occasioned by some recent development work on our tools. As so often happens, developing this code has been a bit of a journey ofContinue reading “DFSORT Tables”

(Originally posted 2015-12-22.) I can cope with both “zee” and “zed”. [1] I love the myriad ways of pronouncing “CICS”. I can even detect such things as “Day Bay Tway” when I hear them. But there are a couple of things that I’m slightly bemused by: People saying “zee-oss” or “zed-oss” or “zoss”. People callingContinue reading “Tis The Season”

(Originally posted 2015-12-22.) WLM will give up on an unachievable goal, eventually. Recently I came across a customer who didn’t know this and for whom this was a big problem.[1] This customer, like many others, was running heavily constrained for CPU. [2] But it does have consequences. In this particular case they had defined twoContinue reading “Overdoing It”

(Originally posted 2015-12-19.) After writing Reviewing The Situation I got thinking. [1] I’ve known for a long time the WLM Policy (XML) has timestamps in it. The thought was “maybe there’s value in doing timestamp analysis”. Here is a fragment of a real customer policy, showing a resource group definition: It’s pretty easy to read.Continue reading “WLM Policy Timestamp Analysis”

(Originally posted 2015-12-14.) I might have written about this before but it’s such a nebulous subject Web searches don’t enable me to tell. In any case it’s a subject worth reviewing every now and then. The subject is “when to review your WLM policy”. I’ve written extensively on how to look at a policy. WhileContinue reading “Reviewing The Situation”

(Originally posted 2015-12-10.) I’ve been very lucky (and kept busy and challenged) these last two months. In addition to my usual case load of customer situations I’ve had the enormous privilege of participating in the ITSO 2015 Mainframe Topics tour. I’ve presented whole-day sessions on Performance and Availability in five cities: Amsterdam, Paris, Warsaw, ViennaContinue reading “Thanks In Five Languages – ITSO 2015 Tour”

(Originally posted 2015-12-07.) Not to be confused with Notational Velocity. A recent customer situation reminded me of how our code calculates velocity. It’s worth sharing with you. The standard way of calculating velocity is to compute (Using Samples)/(Using Samples + Delay Samples) and convert to a percentage by multiplying by 100.[1] The numbers are allContinue reading “A Note On Velocity”