Category Archives: Uncategorized

(Originally posted 2008-06-12.) It’s fair to say I’ve written very little in terms of book words these past two days. That’s because I’ve been “doing research” on how the cache structure counters really work. “Doing research” is a euphemism for “finding out how the heck the darned thing works”. Which is in itself a positiveContinue reading “Cache Structure Information”

(Originally posted 2008-06-10.) I had to eat a little bit of humble pie today – because I made an elementary mistake. I’m going to share it with you – to save you making it, too. 🙂 And I’m very sure I’m not going to make it in a customer situation. (Residencies are great for makingContinue reading “Coupling Facility Structure CPU Time – Initial Investigations”

(Originally posted 2008-06-04.) Sometimes reading the SMF manual buys you less than you thought. I had completely ignored a nice little field – and the code I inherited to analyse SMF 74 Subtype 4 Coupling Facility data ignored it as well. R744SLEC in the Request Data Section for a structure is described by the textContinue reading “A Minor Fact About Lock Structures”

(Originally posted 2008-05-27.) The other three residents are busy doing extensive setup work – and we hope to have some nice measurements later on. (I’m not sure how much later on there actually is, mind.) 🙂 So I have no RMF or DB2 SMF to play with yet. 😦 > Meanwhile I’m beginning to comeContinue reading “Is It The Structure Or The Content That’s Important?”

(Originally posted 2008-05-23.) So, I’m about to start writing. At last! As a team we had a discussion yesterday about how to deal with performance numbers. One of the roles I’m playing on the team is “the guy who writes about performance numbers”. So we came to the following conclusions: We really can’t talk aboutContinue reading “Performance Numbers and the Redbook”

(Originally posted 2008-05-20.) I feel like I’m on “home turf” at UKCMG… My use of English can be looser 🙂 and it’s so nice to catch up customers with whom I’ve a long and (I hope) fruitful history. I did my (slightly updated) “Memory Matters” and “Much Ado About CPU” presentations – and I reallyContinue reading “Goodbye UKCMG, Hello Poughkeepsie”

(Originally posted 2008-05-09.) I’m going to try something different this year – and composing this using OpenOffice Writer on my new ASUS EEE PC while flying home is certainly different. But what’s new is not documenting all the bits and pieces I learnt. Instead I’m going to give some impressions: On Monday afternoon we hadContinue reading “System z Technical Conference – Dresden”

(Originally posted 2008-05-03.) I wonder how many of you recognise the terms “READ_COCLASS”, “WARM”, “RFCOM”,”WRITE_DATALIST” and “CASTOUT_DATALIST”. Granted that in that list are two pairs of terms that I believe to be synonymous, but all five are relatively recent enhancements to Parallel Sysplex infrastructure that have a positive impact on DB2 Data Sharing performance (orContinue reading “Misunderstood Coupling Facility Commands”

(Originally posted 2008-05-03.) Tomorrow I fly to Dresden for the annual European System z Technical Conference. It’s at just the time of year when I can decide in my head that Spring has sprung and that Summer won’t be long coming. 🙂 This is a great conference and I always enjoy attending it (and presentingContinue reading “System z Technical Conference – Dresden”

(Originally posted 2008-04-27.) As some of you will know IBM has a twice-yearly “HackDay” programming fest. And the latest – HackDay5 – was last Friday. Couched as a competition it isn’t really… It’s a heck of a sight more cooperative than that. (Else I wouldn’t have got involved.) I’ve participated in all five we’ve hadContinue reading “My HackDay 5 Project – z/OS System Logger Analysis”