Johnny, The maximum size for any single individual page dataset is 4GB. You can define up to 253 local page datasets per MVS image, so the actual maximum amount of AUX storage is 253 times 4 Gibibytes (or Gigabytes for the standards-challenged). That is roughly (but not quite) 1 terabyte of concurrently usable virtual storage per MVS LPAR. (I just checked the z/OS 1.7 DFSMS documents and that limit seems to be true up through that release at least.)
The above is as of the announced release of z/OS (and below - that limit hasn't been meaningfully changed in over a decade). I believe that limit needs to be raised, somehow, in a reasonably near-term future release although it might not be raised by increasing the PAGE=/NONVIO= parameters in IEASYSxx. For example, they might want to allow for a larger virtual storage slot size using differently formatted AUX datasets. (Perhaps even allowing such datasets to exist on non-CKD devices?) 4K slot size is extraordinarily limiting when 64-bit storage is considered. I suspect they will allow for some method of writing 1M segments per "slot" (and I suspect they might use a different term than 'slot' for such, too). The previous 2 paragraphs are wild speculation on my part. (Lets see how I do in a few years, eh?) On Fri, 10 Feb 2006 23:41:15 +0800, Johnny Luo wrote: >MVS(Multiple Virtual Storage) is the basic concept for z/os.However,after >entering the mainframe world for eight months I still cannot understand it >thoroughly! (Especially for ' multiple address spaces'.) > >To make things simple,I'll assume 31-bit addressing only. > >1,MVS allow different task to have their own address space.While the number >of address space increases in system,the total amount of virtual storage >can become very big. >However,as I know,virtual storage is supported by real storage and >auxiliary storage. With 31-bit addressing,the max size of real storage or >auxiliary storage is 2G. > So,the max size of virtual storage=max real storage+max auxiliary >storage=4G > Does this mean that the total size of all the address spaces cannot >exceed 4G although in theory each address space can have a max size of 2G? No, see above. The max size of all the address spaces is currently limited to approximately 1 TB. -- Tom Schmidt Madison, WI ---------------------------------------------------------------------- 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
