According to this (somewhat old) redbook, the same amount of space is used. http://www.redbooks.ibm.com/redbooks/pdfs/sg246979.pdf
>From the "SMS enhancements" chapter: "If a data set, with one primary and five candidate volumes was in a data class with a DVC of less than 7, then 24 bytes of TIOT space is required. If the same data set was using a data class with a DVC of 20, then it would require 80 bytes of TIOT space." It also says this: "Note: DVC for VSAM striped data sets is supported even though they are not eligible for Space Constraint Relief." Is that more or less confusing? :-) Greg Shirey Ben E. Keith Company -----Original Message----- From: IBM Mainframe Discussion List On Behalf Of Mark Zelden Sent: Wednesday, March 26, 2008 4:14 PM To: IBM-MAIN@bama.ua.edu Subject: Re: Displaying multiple volumes allocated from DSLIST It does cost. It takes space in the TIOT. IIRC, 4 bytes for each candidate. Depending on how many DDs are in a step and the TIOT size defined in ALLOCxx this could cause a problem. It also can have an effect on catalog space requirements. In z/OS 1.3 IBM came up with DVC (Dynamic Volume Count) which only stores the volumes specified / used in the catalog. I'm not clear if it still takes up the same amount of space in the TIOT - I would have to research that. But now I am a little confused... the z/OS 1.6 manual that I opened up just said that DVC is "a feature supported only for multi-striped VSAM data sets" and had the "changed bar" (|) next to it. I am leaving for the day so someone perhaps can shed some light on this and I'll follow up tomorrow. ---------------------------------------------------------------------- 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
