>If I were doing I/O performance measurement and tuning today, I would most >definitely not use that number.
Why not? That is what it is -- constant. I'm pretty sure it's derived from the equation 128 mics * 6500 = 8.32 ms. >Since you are using the number, you should verify its accuracy and, if not >accurate any more, ask IBM yourself or else find a more modern analysis of >average I/O service time. The number is good for the 'quick and dirty'. I never said that Ron's suggestion for the analysis of I/O from RMF (etc) was wrong. Nor did I say I was using the number, myself. I was just disputing the comment that EXCP's were only block counts. That depends on the setting (TIME or COUNT). And, I believe COUNT is still the default. - Too busy driving to stop for gas! ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html