Thomas, I don't believe this is true. There are files systems that require pre-allocation of space.
In fact the use of a raw LUN is predefined space by definition. If you spent some setting up arrays for large Open Systems servers where they want 120 different LUN sizes you see the similarity. The PC disk NTFS model is not a valid comparison with a z/OS file system. Go and look at a couple of 100TBs of squatty box storage like you have in z/OS. Pre-allocated space in LUN units is rife through Open Systems - as is a significant amount of wasted free space :-( Oh, and automatic extension of a file from one LUN to another for 59 LUNS is a foreign concept in Open Systems File systems. They're still wishing for one. They have to go through a Dynamic LUN Expansion process to manage that one - always fun at 3 in the morning. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On Behalf Of > Thomas Berg > Sent: Monday, February 13, 2012 3:28 AM > To: IBM-MAIN@bama.ua.edu > Subject: [IBM-MAIN] Archaic allocation in JCL (Was: Physical record size > query) > > I can't understand why we STILL need to specify SPACE= (etc) for an allocation > of a dataset. > You normally don't do that in other OS (platforms), You always (both > principally and in practice) want to allocate as much as is needed during > execution > > If for backward compatibility it can't be done automatically, why not > introduce a new keyword like e g "SPACE=ANY" ? > > > > Regards, > Thomas Berg > _________________________________________ > Thomas Berg Specialist A M SWEDBANK > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email to > lists...@bama.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
