I suppose that, since the actual format of an extended format data set isn't published, changes to the format won't be either.
However, it is clear that each block in (any) extended format data set has a suffix appended. From a SHARE 141 presentation, a v1 EF data set suffix contains a block number which is volume dependent and version 2 removes that volume dependency. Available in z/OS DFSMS 2.1 with compatibility PTFs for unspecified earlier releases. A bit more hunting reveals section 4.4 (p72ff) in the z/OS 2.1 DFSMS update redbook, SG24-8190, with similar information. Sadly there don't seem to be redbooks for DFSMS after this. HTH Nigel Morton On Sun, 4 Apr 2021 at 00:47, Lennie Dymoke-Bradshaw < [email protected]> wrote: > Radoslaw, > > I have looked in a lot of places for the differences between version 1 and > version 2 Extended format data sets. I have asked questions of IBM and not > got answers. The only place I have found anything is in the description of > the EXTPREF parameter of DSNTYPE in the JCL reference manual. It explains > how behaviour may be different, but not any details of the underlying > changes. I suspect that is information only available to those who fully > understand the contents and role of those extra 32 bytes on each physical > block. > > Lennie Dymoke-Bradshaw > Consultant working on contract for BMC mainframe Services by RSM Partners > ‘Dance like no one is watching. Encrypt like everyone is.’ > > > -----Original Message----- > From: IBM Mainframe Discussion List <[email protected]> On Behalf > Of Radoslaw Skorupka > Sent: 03 April 2021 23:04 > To: [email protected] > Subject: Re: Stand Alone Dump questions > > Jim, > > It is not related to SADUMP, but definitely related to z/OS: > You mentioned extended format PS is restricted to ~4Gi blocks per volume. > Where is it documented? > This is information I'm trying to find and sometimes I see some clues, but > no reference to the documentation. > > Another question: what about "format 2" of ext-fmt PS? Is there any > documentation or presentation clarifying the differences? > > BTW: I know there is limitation for EAV, which is currently approx. 1TB, > so ext fmt block count limitations is rather too big. > > -- > Radoslaw Skorupka > (looking for new job) > Lodz, Poland > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
