The VTOC will be wherever it was placed during volume initialisation. It is not in any fixed position. The IPL records are distinct from the VTOC.
Using ABSTR may be possible, but you will almost certainly have a problem using a DSN parameter as whatever you place there will get a 213-04 abend. So, it may require opening another data set on the volume and then altering the DEB after it is opened, so that the extents in the DEB cover the tracks you want. Dodgy stuff. I have tried to use ADRDSSU to copy cylinder 0, to another data set but I keep getting a problem with IGWNOTIF (RC=8, Reas=121A0802). Given that I am doing nothing with PDSEs I think this may be a bug. Lennie -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Mike Shaw Sent: 13 February 2024 22:22 To: [email protected] Subject: Re: How read Cyl 0 from within a program? I have used this JCL to open a VTOC to read it: //DD1 DD UNIT=3390,DISP=SHR,DSN=FORMAT4.DSCB,VOL=SER=xxxxxx The VTOC might be adjacent to track zero, but I am not sure the DEB for an open VTOC would include track zero. Mike Shaw MVS/QuickRef Support Group Chicago-Soft, Ltd. On Tue, Feb 13, 2024, 1:19 PM Charles Mills <[email protected]> wrote: > I am interested in writing a program to read the IPL records from a > DASD volume. (Read only, not update). I am comfortable with XDAP but > how do I OPEN a "dataset" that would include cylinder 0? > > APF, OPERATIONS and so forth are not out of the question. > > Thanks, > Charles > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
