I'm curious about the experiment that shows something on disk. ZAP command says 'DATA SET UNAVAILABLE OR NON-EXISTENT'. IEHLIST says '----THE ABOVE DATASET HAS NO EXTENTS'. What view of the disk shows something on a data track?
. . JO.Skip Robinson SCE Infrastructure Technology Services Electric Dragon Team Paddler SHARE MVS Program Co-Manager 626-302-7535 Office 323-715-0595 Mobile [email protected] From: Paul Gilmartin <[email protected]> To: [email protected] Date: 08/25/2012 09:50 AM Subject: Re: Space Allocation In Bytes Sent by: IBM Mainframe Discussion List <[email protected]> On Sat, 25 Aug 2012 08:49:49 -0700, Skip Robinson wrote: >Zero space allocation is perfectly valid. As is SPACE (0,1) also. The >result is just as requested. In either case, the data set exists in the >VTOC but takes up no space on disk. > Ummm... no. By experiment, it allocates one track. There has to be room for the count field. And SPACE=(65535,1) allocates two tracks. This surprises me. Does 3390 support blocks spanning tracks? Also surprisingly, SPACE=(0,99999) allocates 8,334 tracks; SPACE=(1,99999) allocates 1,163 tracks. Did I do something wrong? Did someone divide by zero? >The data set is treated as 'real', >including GRS enqueue. Hence it can be used like any other exclusively >held data set to serialize execution. > The data set's being 'real' has little to do with GRS enque. I can code: //GRS EXEC PGM=WOMBAT,COND=(0,LE) //SERIAL DD DISP=OLD,DSN=NONE.SUCH The data set needn't exist; the step isn't executed; yet I believe an exclusive ENQ is issued for its name which could be used to serialize execution. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
