Gerhard, Nothing wrong with what you said, but IOSERV uses connect time, which is handshake and transfer and represents work being done by the CEC. If everything else you mentioned was to be included then why not use the sum of Connect, Disconnect and Pend (Service Time) to calculate IO Service Units?
Ron > > I would be surprised if it isn't, although I'd use a value a > little smidgen higher. The typical I/O requires some setup to > get IOs to handle the request, it needs to be queued, wait until > the device is available, position the heads, search or seek the > record, transfer the data, and clean up. Processors in the late > eighties were fast enough so that only the search or seek > processing took any significant time compared to processing > time. If the disks were favorably positioned at the time of > request, there would be no overhead, vs. maximum overhead if it > just passed the requested record. So half the latency represents > an average; I'd also add a correction factor for arm > positioning, but if you're the only one running, after the first > I/O that also becomes negligible. > > > Gerhard Postpischil > Bradford, VT > > ---------------------------------------------------------------------- > 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 ---------------------------------------------------------------------- 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
