I guess the question is not so basic. Many years ago, we did some batch tuning. We found that reducing QSAM I/O by 20 percent also reduced CPU by 5% or so (plus or minus senior fudge factors). But, IMHO, there are far too many variables and far too many unknowns to even offer a SWAG for your situation.
Even if there were such a metric, I would suspect it would not be linear. Perhaps you could run down the Gartner tome that suggested that hardware is going to make up less than 20% of the total budget. If that is true, then I wonder what you would gain by knowing the answer to your question. One trick I used in my capacity modeling days was to just pick a value for an unknown, then vary the value until it made a difference. With those numerical models, the threshold point was often abrupt and dramatic. In your case, perhaps you could set an impossible endpoint where your new application used zero CPU, then crunch the numbers against the current application. By knowing both endpoints, you could gain some insight as to your scope. Perhaps add some intermediate data points by postulating a CPU decrease of, say, half. Also consider that any redevelopment is going to consume CPU. There is no free lunch here. HTH. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Ted MacNEIL Sent: Monday, April 10, 2006 7:00 PM To: [email protected] Subject: Re: A very basic question >Where did the number 10K come from? >What was measured? It came from IBM over 20 years ago. If you look at my original post, I was asking if it was valid. Not stating it as a fact. So far, I've gotten a lot of tuning recommendations and a maybe. None of that has answered my question. We are attempting to size a re-development effort. And, the tuning recommendations, while valid, are not addressing the question. Nor does a maybe, or an asking where the number comes from. Can anybody answer the question: "What does it cost, in instructions (approximately) to do a VSAM I/O?" - -teD ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
