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Hello, I'm Martin And I'm An Algebraic :-)
If you're sat next to me on a plane you'll probably notice at take off and landing I do algebra puzzles. You may not have heard of the term "algebra puzzles" before and perhaps think the juxtaposition of the two words to be odd, but I think it apt...
(You may also think this whole post to be showing off, but that's a risk I take in sharing a passion I have.)
A classic problem... [More]
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10,000 Hours Doing WHAT?
It's a popular suggestion that what separates the truly exceptional
person from the rest of us is 10,000 hours of "practice". In book form
I've seen it twice - in Matthew Syed's "Bounce" and in Malcolm Gladwell's "Outliers" . Actually, to be fair, Matthew acknowledges his
original source so that's actually only one distinct source. (Life Lesson aside: Trace... [More]
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Capacity, Performance and Systems Investigation
At one level Performance and Capacity Management and Systems Investigation are clearly linked: They share the same data. Or much of it at least. But I think they're linked in another way, too. Over the past few years I've gradually shifted emphasis towards Systems Investigation. But this has only been a slight shift, a "non modo sed etiam" and still only really mainframe. So I'm... [More]
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Why Do We Keep Building Bigger Machines?
I know of no customer who uses the full capacity of a zEC12, let alone a z13? 1 So why do we make them bigger each time? I should state this post is not in support of any product announcement; It’s just scratching an itch of mine. I think it’s an interesting topic; I hope you agree. What Is Bigger?
While this post isn’t exhaustive I think the main aspects are:... [More]
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I Know What You Did Last Summer - Abstract
Here's the first-pass abstract slide for "I Know What You Did Last Summer". I'd be interested in your thoughts on it... What's The Point Of This Presentation? So, it's got a "tongue-in-cheek" title but what's it all about? I think one of the least appreciated aspects of z/OS and its middleware is the richness of instrumentation it gives you. Here I describe it and just some of... [More]
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XML, XSLT and DFSORT, Part Three - Multiple XML Input Files
While I was putting together the original three posts in this series a number of thoughts struck me, amongst which two really cried out for further investigation: I don't know how your XML data arrives on z/OS but quite a lot of scenarios don't have the data all as one document (file). XSLT looks complex - particularly if recursion does your head in. Thought 2 I'll deal with in a... [More]
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HTML5 Up and Running - A Review Of Sorts
William Gibson's "The future is already here — it's just not very evenly distributed" applies very well to HTML5. It's even more true of CSS3. Despite that (or maybe because of it) it's a good time to dive into HTML5 - before everyone else does. So, a few months ago I bought, read and inwardly digested Mark Pilgrim's HTML5 Up and Running , published by O'Reilly in August 2010. I have a... [More]
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Experimenting With QR Codes
Inspired by two of Bob Leah's posts on QR Codes - here and here I started experimenting with creating and consuming QR codes. But what is a QR code? In short it's a two-dimensional barcode that can contain e.g plain text or a URL. In the latter case a QR code reader can pick up the URL - maybe from a real-world object - and open it in a browser.
Creating QR Codes In my experiment I created the... [More]
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Batch Architecture, Part Zero
I'm not an architect. I don't even play one on TV. In fact real architects would probably say I'm in the babble phase, architecturewise . But I've been involved in a few situations over the past year or so (and I'm involved in a couple starting round about now) which have led me to the following simple conclusion: Many installations would benefit from drawing up a Batch Architecture . I don't... [More]
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Do You Like The New Look?
I hope you do. Special thanks are due to Bob Leah, Victoria Ovens and David Salinas for getting me this far: Bob created the new template I'm using (and it is discussed further here . Victoria created the new blog header graphic (of a z196 and a zBX) and David put it up for me. You'll have noticed I'm also blogging again - after a gap of about a year. (I talk about that somewhere in the middle of... [More]
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When Display Commands Aren't Good Enough
There've been times in the past when a request for extra data in SMF has been met by "you can issue a DISPLAY command to get that".
(Another variant is "you can go to the HMC for that".) I'm here to tell you why I don't think that's a brilliant answer: Such a command is a point-in-time thing.
Systems nowadays are much more dynamic than they were. Something as simple as... [More]
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WLM Velocity - "Rhetorical Devices Are Us"
I'm beginning to look at performance data slightly differently these days... As well as plotting things by Time Of Day (which our tools have done for 25 years) I'm beginning to plot things more directly with load. (Time Of Day is sort of code for With Load but not really - telling a story people can relate to more directly.) The first instance of this "with load" approach was plotting... [More]
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Mainframe Performance Topics Podcast Episode 17 "Two Good, Four Better?"
This episode really has been a long time coming. If I reflect on why, there are two things… The main one is our schedules. Marna and I, as you’ll see, have been all over the place. The minor one is that - until about a month ago - I wasn’t on a creative streak. Nothing major, it happens. And I’m certainly on one now. We certainly hadn’t got bored of doing this - and... [More]
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What Is This DB2 Subsystem For?
“What is this DB2 subsystem for?” is an important question - at least to me. And explaining this topic over lunch to a friend of mine who was a DB2 developer, convinced me it has more general importance. If you’re a DB2 sysprog or DB2 the answer is probably well known to you 1 . If you’re not a DB2 person it’s probably not so obvious. Something worth noting at this... [More]
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How Does Transaction CPU Behave?
If a customer has Transaction goals [1] - for CICS or IMS - it’s possible to observe the CPU per transaction with RMF. But you have to have: Transaction rate CPU consumed on behalf of the transactions. This might seem like stating the obvious but it’s worth thinking about: The transaction rate and the CPU consumption have to be for the same work. Now, a Transaction service class... [More]
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Reviewing The Situation
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. While I think you should read
Analysing A WLM Policy - Part 1 I want to refer to... [More]
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A Note On Velocity
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 all recorded in SMF Type 72 Subtype 3. We have two main graphs... [More]
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Captivating Capture Ratios
I don’t think I’ve written about the concept of Capture Ratio [1] before.
To be honest it’s kind of a “nerdy” or “internal” thing.
But a recent experience suggests to me it is interesting, even if only for the wrong reason. What Is Capture Ratio? Not all CPU in a z/OS system can be attributed to a service class:
If you add up all the CPU in SMF... [More]
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How I Look At Virtual Storage
I thought I’d write about how I begin looking at virtual storage, occasioned by a customer who had a 24-bit virtual storage (878–10) ABEND [1] .
Most of this is in our code, so easy for me to do.
I hope you’ll find it similarly easy. You’ve had hints of this in
How Many Eggs In Which Baskets? and
Broker And SMF 30 . The game is really to use product-neutral... [More]
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Coupling Facility Memory
Or “who made all the pies”? I’ve written a number of times about Coupling Facility Performance but I don’t think I’ve written about memory for a while. In any case I’d like to share with you a couple of graphs I’ve taught my code to make. The first isn’t strictly speaking specific to Coupling Facilities. But it’s useful anyway and does help... [More]
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