"Ted MacNEIL" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>... > .. > So, I ask, is I/O tuning still possible, or even necessary? > .. > > I've got a related question. > Our service provider is attempting to get us more channels into > our single DASD controller. > We have four. > We have no Channel Busy Delay. > We have more than adequate response time. > They have supplied no evidence, as yet. > > My question is: > > What is considered "too busy" these days for channels? > > With the advent of all the changes to the channel sub-system since XA (and onward), > I believe you can run them quite high, well over 50%. > > Since (the simple equation), the odds of all four being busy is: > > 5 ** 4 = .125 > > Or 12.5% of the time there would be no channel busy. > Of course, you have to calculate the 'Relative Path Busy', since your own I/O doesn't count. > But, I did say 'simple'. >
Beware: .5 **4 = 0.0625, 6% of the time no path is busy. It also means that (1-.5) ** 4 = 0.0625 6% if the time all paths are busy and you will encounter delays and this sounds a little high to me. .5 ** 6 = 1.5% all paths busy .6 ** 8 = 1.6% all paths busy Kees. ********************************************************************** For information, services and offers, please visit our web site: http://www.klm.com. This e-mail and any attachment may contain confidential and privileged material intended for the addressee only. If you are not the addressee, you are notified that no part of the e-mail or any attachment may be disclosed, copied or distributed, and that any other action related to this e-mail or attachment is strictly prohibited, and may be unlawful. If you have received this e-mail by error, please notify the sender immediately by return e-mail, and delete this message. Koninklijke Luchtvaart Maatschappij NV (KLM), its subsidiaries and/or its employees shall not be liable for the incorrect or incomplete transmission of this e-mail or any attachments, nor responsible for any delay in receipt. ********************************************************************** ---------------------------------------------------------------------- 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
