Author Archives: Martin Packer

(Originally posted 2011-07-19.) It may surprise you to know I hate asking questions to which I already know the answers. And I hate even more "leaving understanding on the table". Let me put it more positively: I love it when I can glean new insights into existing data. This post is about precisely that: AnContinue reading “An Experiment With Job Naming Conventions”

(Originally posted 2011-07-17.) Frank Yaeger of DFSORT Development suggested I pass this tip along to y’all. It’s his solution to a problem set by Brian Peterson of UnitedHealth Group… In z/OS Release 12 two new messages were introduced: IEF032I and IEF033I replace IEF374I and IEF376I. The older messages were single-line step- and job-end messages. TheContinue reading “Multiline Message Sifting With DFSORT”

(Originally posted 2011-07-09.) 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 alsoContinue reading “Hello, I’m Martin And I’m An Algebraic :-)”

(Originally posted 2011-07-07.) 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 oneContinue reading “10,000 Hours Doing WHAT?”

(Originally posted 2011-07-05.) As you probably know Hardware Data Compression has been supported by MVS and IBM mainframes for around 20 years. In several recent batch studies I’ve conducted it’s been evident in a widespread way. (In this post I’m not talking about DB2 compression of either flavour or VSAM compression – though some ofContinue reading “Recent Experiences With Hardware Data Compression”

(Originally posted 2011-07-02.) Following on from The Best Sort Is The One You Don’t Do here’s another reason for eliminating sorts. I think it’s worth a post in its own right. (In this post, again, I’m talking about resequencing passes over data – not copying or merging.) With a sort it’s possible the last recordContinue reading “Another (Perhaps Obvious) Reason For Avoiding Unnecessary Sorts”

(Originally posted 2011-07-02.) Have you ever had the suspicion a sort was unnecessary in your batch? I bet you have. In recent Batch Performance studies I’ve had the suspicion that many of the sorts are unnecessary: Either they should be merges or not done at all. But how do you prove it?  But first, whatContinue reading “The Best Sort Is The One You Don’t Do”

(Originally posted 2011-06-29.) This may be stating the obvious – but I wonder to whom it actually is obvious… I’ve been doing quite a lot of work with batch job timings and CPU recently. (Everything I’m about to say is equally true of steps.) It’s interesting to think about the effects of faster engines versusContinue reading “It Depends: SMF 30 Job Timings And CPU Time”

(Originally posted 2011-07-19.) Here’s another neat piece of algebra: A technique for summing series. You know what b – a + c – b + d – c is. Right? Suppose I were to write the same sum as: (b – a) + (c – b) + (d – c) The answer is still dContinue reading “Memory Breakdown in Firefox”

(Originally posted 2011-06-22.) A need has arisen for pretty printing XML. This post includes some Python code to do it. I’ve been working with the OpenOffice.org ODP presentation file format recently: I want to generate presentations from application code. An ODP file is a structured zip file. Among other items it contains an XML fileContinue reading “Pretty Printing XML in Python”