DB2 Instrumentation Changes – Documentation Updated

(Originally posted 2005-07-11.) APAR PQ96908 accumulates updates to the DB2 for OS/390 and z/OS V7 and V8 IFCID flat files (DSNWMSGS) that occur in the last half of 2004 and the first half of 2005. DSNWMSGS documents all the fields in each of the DB2 SMF records (and other DB2 instrumentation sources). Personally I carryContinue reading “DB2 Instrumentation Changes – Documentation Updated”

Paging Subsystem Design

(Originally posted 2005-07-05.) Periodically on IBM-MAIN I’m caused to revisit something. With the advent of z990/z890 and “supposedly abundant” 🙂 real memory it seems to be time to revisit paging subsystem design. You might perhaps think that in these days of zero paging you could skimp on paging subsystem design. And you’d be wrong. 😦Continue reading “Paging Subsystem Design”


(Originally posted 2005-06-29.) As a relative newcomer to the world of web programming I’ve been learning javascript. The reason I chose this language is (quite apart from already knowing java/swing) there is a very useful javascript tool called GreaseMonkey. Greasemonkey allows you to modify web pages you’re browsing. Such modifications include Inserting HTML into aContinue reading “GreaseMonkey”

Things I could write about

(Originally posted 2005-06-15.) Yesterday we IBM “pioneer” bloggers had a conference call where we thought about enhancements to this blogging site. One that seemed to get some measure of support was the notion of a place where readers could make unsolicited comments and ask questions. I’m just writing about things I think are interesting. I’mContinue reading “Things I could write about”

DB2 Virtual Storage Goes Mainstream

(Originally posted 2005-06-13.) For a number of years now we’ve been talking about the importance of DB2 Virtual Storage management. The real credit goes to John Campbell of the DB2 lab who pioneered this stuff. We usually see DB2 Virtual Storage as an issue in 2 ways: A client presents with the problem and asksContinue reading “DB2 Virtual Storage Goes Mainstream”

Learn from my mistakes – Which Engines Does IRD Vary Offline?

(Originally posted 2005-06-13.) I’d made the assumption (in my code) that IRD would vary offline the top logical engines when it decided to vary an LPAR’s logical engine offline. In fact that isn’t the case. I have data from a US company where it’s engines 2 and 3 (out of the range 0-11) that tendContinue reading “Learn from my mistakes – Which Engines Does IRD Vary Offline?”

DB2 Accounting Trace Parallel Task Rollup – A Problem Child?

(Originally posted 2005-05-09.) Here’s another breakage of Accounting Trace that’s been fixed: APAR PK03905 describes a problem with DB2 Parallel Task Rollup that causes the Group Buffer Pool Accounting data for GBP 0 to be missing. (Its title talks about IFCID 148 but in the detail IFCID 3 is roped in. IFCID 3 means “AccountingContinue reading “DB2 Accounting Trace Parallel Task Rollup – A Problem Child?”