> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:ibm-m...@bama.ua.edu] On Behalf Of Tom Marchant > Sent: Tuesday, February 23, 2010 11:41 AM > To: IBM-MAIN@bama.ua.edu > Subject: Re: LPARs: More or Less? > > On Tue, 23 Feb 2010 11:24:55 -0500, David Andrews wrote: > > >didn't bare MVT have a horrendous core fragmentation > >issue? > > Suppose that you have a 768K machine and the memory is mapped > like this (I'm making up these numbers, and I don't remember where > everything was located): > > 0-200K Nucleus > 200K-600K > 600K-640K SQA and CSA > 640K-768K LPA > > All your initiators run in the area from 200K to 600K. Suppose you > start a job that needs 110K. It gets the area from 200K to 310K. > While that job is running, you start another job that needs 200K. > It will reside from 310K to 510K. > > After the first job ends, there is a total of 200K available, > but it is not > contiguous. You can run a job that needs 110K and one that > needs 90K, > but nothing larger. > > At the MVT shop where I worked, we had a fixed number of initiators > that each had their assigned Job classes. To ensure that storage > would not be fragmented, we had region size standards for each job > class, and all job classes for a particular initiator were > required to use > the same region. > > -- > Tom Marchant
I remember that we had a "cheat" in MVT. We had an RYO tp monitor. Somebody, before my time, made a mod to GETMAIN so that a request for a ODD sized REGION would get the storage from the high end of free storage. We ran the tp monitor with an ODD region size so that it always "ran high" and so did not get in the way of batch regions. This place, Braniff Airways, actually ran MVT without HASP because "HASP cost too much in resource". Very strange place to work. Job "sysout" was always directed to tape. Then the operators had a tape to print STC which could do forward and backward spacing via the console. -- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets(r) 9151 Boulevard 26 * N. Richland Hills * TX 76010 (817) 255-3225 phone * (817)-961-6183 cell john.mck...@healthmarkets.com * www.HealthMarkets.com Confidentiality Notice: This e-mail message may contain confidential or proprietary information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. HealthMarkets(r) is the brand name for products underwritten and issued by the insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake Life Insurance Company(r), Mid-West National Life Insurance Company of TennesseeSM and The MEGA Life and Health Insurance Company.SM ---------------------------------------------------------------------- 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
