> -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] > On Behalf Of Greg Dyck > Sent: Tuesday, September 13, 2016 1:14 PM > To: [email protected] > Subject: Re: Internals of Catalog > > On 9/13/2016 11:55 AM, Jake Anderson wrote: > > Can some one please explain the Catalog internals with respect to the > > VVDS and VTOC. > > At the 10,000 ft level... > > The catalog is a VSAM KSDS dataset that (mostly) points to the volume > containing the dataset. > > The VTOC contains where on the volume, by cylinder and track, any datasets > live, be they VSAM or non-VSAM. > > The VVDS contains VSAM unique information for any VSAM datasets that are > contained in the VTOC.
For SMS datasets, the VVDS also contains some of the SMS related data for non-VSAM > > A VSAM catalog entry is actually a composite of the catalog, the VTOC, and > the VVDS information merged together. > > Regards, > Greg > > ---------------------------------------------------------------------- > 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
