Tom, The following commends are on the question of why you get different results with a DISP=NEW and a DISP=OLD data set.
With DISP=NEW, except for the first volume, until you write to a volume there is, logically, no volume. You only create the operating system structures for a new volume when EOV is driven and that EOV forced a new volume. I have done what you are talking about for both DISP=OLD and DISP=NEW data sets. It is difficult and you have to basically open a DCB for each volume. With DISP=NEW, the first DCB you open will always be associated with the last volume written to. This is because when you issue an EOV and you go to a new volume, the DCB and other control blocks are disassociated with the old volume and are now associated with the new volume. To get to the previous volume, you have to open a new DCB pointing to the previous volume. With DISP=OLD life is much easier, unless you are going to extend the data set. In that case you can open a DCB for each existing volume. If you extend the last dataset by doing an EOV, the DCB that was pointing at the last will now be pointing at the new last volume. If you want to get at the old last volume you have to open a new DCB pointing at the old last volume. Have I confused you enough? Please contact me offline if you have more questions that you think I can help you with. Chris Blaicher BMC Software, Inc. 512-340-6154 -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Tom Quarendon Sent: Monday, February 04, 2008 10:08 AM To: [email protected] Subject: Re: Trouble opening specific volumes with OPEN TYPE=J I've tried a number of things, but typically just VOLUME=SER=(volser1,volser2,volser3,volser3) I've also tried UNIT=(SYSDA,4) VOLUME=(,,,4) and I get the same problem. J R wrote: > Are you specifying vol-count on your allocation? > > What does your allocation look like? ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
